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详细介绍Python公共方法

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python, python教程
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<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中有很多内置函数和标准库函数，它们被称为Python的公共方法。这些方法可以帮助开发人员更高效地编写代码，实现各种功能。下面是一些常用的Python公共方法的详细介绍：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">1. print()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">print()是Python内置的一个函数，用于输出指定的信息到控制台。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，value是要输出的值，sep是分隔符，默认为一个空格，end是行末字符，默认为一个换行符，file是输出文件对象，默认为sys.stdout，flush是一个布尔值，表示是否立即刷新输出缓冲区，默认为False。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">2. input()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">input()是Python内置的一个函数，用于接收用户从控制台输入的数据。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">input(prompt=None)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，prompt是提示用户输入的字符串，默认为None。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">3. len()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">len()是Python内置的一个函数，用于返回一个序列对象的长度。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">len(s)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，s是要计算长度的序列对象。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">4. range()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">range()是Python内置的一个函数，用于生成一个整数序列。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">range(start, stop[, step])<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，start是序列的起始值，默认为0，stop是序列的终止值，不包括该值，step是序列的步长，默认为1。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">5. list()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">list()是Python内置的一个函数，用于将一个可迭代对象转换为列表。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">list(iterable)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，iterable是要转换为列表的可迭代对象。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">6. tuple()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">tuple()是Python内置的一个函数，用于将一个可迭代对象转换为元组。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">tuple(iterable)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，iterable是要转换为元组的可迭代对象。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">7. set()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">set()是Python内置的一个函数，用于创建一个集合。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">set(iterable)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，iterable是要初始化集合的可迭代对象。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">8. dict()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">dict()是Python内置的一个函数，用于创建一个字典。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">dict(**kwarg)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">dict(mapping, **kwarg)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">dict(iterable, **kwarg)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，kwarg是一个关键字参数字典，mapping是一个映射对象，iterable是一个包含键值对的可迭代对象。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">9. sorted()<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">sorted()是Python内置的一个函数，用于对可迭代对象进行排序。语法如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">sorted(iterable, key=None, reverse=False)<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">更多Python相关学习，推荐小册：<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;"> Python基础 + Django + 爬虫 + 文档处理<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;"><a href="https://www.maxiaoke.com/manual/python_jcddypc.html" target="_blank"><img src="/uploads/images/20230218/03c2f5e077486036c3ad1cb49199370a.jpg" title="pyth.jpg" alt=""/></a><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">点此查看：<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;"><a href="https://www.maxiaoke.com/manual/python_jcddypc.html" target="_blank" style="text-decoration: underline; font-size: 18px; color: rgb(192, 80, 77);">Python基础Django与爬虫</a><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">

详细介绍Python字典的相关操作

后端
python, python教程
17431 阅读

<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中的字典（dictionary）是一种无序的数据结构，可以存储键值对。字典的键必须是唯一的，而值可以重复或不唯一。下面是Python字典的相关操作：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">创建字典<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用花括号 {} 或 dict() 函数来创建字典，如下所示：<pre class="brush:as3;toolbar:false">my_dict = {} my_dict = dict() my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">访问字典元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用方括号 [] 来访问字典中的元素，如下所示：<pre class="brush:as3;toolbar:false">my_dict = {'name': 'John', 'age': 30, 'city': 'New York'} print(my_dict['name'])  # 输出 John print(my_dict.get('age'))  # 输出 30</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">修改字典元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用方括号 [] 来修改字典中的元素，如下所示：<pre class="brush:as3;toolbar:false">my_dict = {'name': 'John', 'age': 30, 'city': 'New York'} my_dict['age'] = 40 print(my_dict)  # 输出 {'name': 'John', 'age': 40, 'city': 'New York'}</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">删除字典元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 del 关键字来删除字典中的元素，如下所示：<pre class="brush:as3;toolbar:false">my_dict = {'name': 'John', 'age': 30, 'city': 'New York'} del my_dict['age'] print(my_dict)  # 输出 {'name': 'John', 'city': 'New York'}</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">遍历字典<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 for 循环来遍历字典中的元素，如下所示：<pre class="brush:as3;toolbar:false">my_dict = {'name': 'John', 'age': 30, 'city': 'New York'} for key in my_dict:     print(key, my_dict[key]) # 输出 name John # 输出 age 30 # 输出 city New York</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">获取字典的键和值<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 keys() 函数获取字典的键，使用 values() 函数获取字典的值，如下所示：<pre class="brush:as3;toolbar:false">my_dict = {'name': 'John', 'age': 30, 'city': 'New York'} print(my_dict.keys())  # 输出 dict_keys(['name', 'age', 'city']) print(my_dict.values())  # 输出 dict_values(['John', 30, 'New York'])</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">合并字典<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 update() 函数将一个字典的键值对合并到另一个字典中，如下所示：<pre class="brush:as3;toolbar:false">my_dict1 = {'name': 'John', 'age': 30} my_dict2 = {'city': 'New York'} my_dict1.update(my_dict2) print(my_dict1)  # 输出 {'name': 'John', 'age': 30, 'city': 'New York'}</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">以上是Python字典的常见操作，可以根据需要进行使用。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;">

详细介绍Python元组的相关操作

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python, python教程
10833 阅读

<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中的元组（tuple）是一种有序的数据结构，类似于列表，但是元组是不可变的，一旦创建就不能修改。下面是Python元组的相关操作：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">创建元组<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用圆括号 () 或 tuple() 函数来创建元组，如下所示：<pre class="brush:as3;toolbar:false">my_tuple = () my_tuple = tuple() my_tuple = (1, 2, 3)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">访问元组元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用索引来访问元组中的元素，索引从0开始，如下所示：<pre class="brush:as3;toolbar:false">my_tuple = (1, 2, 3) print(my_tuple[0])  # 输出 1</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">切片元组<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用切片来获取元组的子集，如下所示：<pre class="brush:as3;toolbar:false">my_tuple = (1, 2, 3, 4, 5) print(my_tuple[1:3])  # 输出 (2, 3)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">拼接元组<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用加号 + 来拼接两个元组，如下所示：<pre class="brush:as3;toolbar:false">my_tuple1 = (1, 2, 3) my_tuple2 = (4, 5, 6) my_tuple3 = my_tuple1 + my_tuple2 print(my_tuple3)  # 输出 (1, 2, 3, 4, 5, 6)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">复制元组<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用乘号 * 来复制元组，如下所示：<pre class="brush:as3;toolbar:false">my_tuple = (1, 2, 3) my_tuple2 = my_tuple * 2 print(my_tuple2)  # 输出 (1, 2, 3, 1, 2, 3)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">获取元组长度<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 len() 函数获取元组的长度，如下所示：<pre class="brush:as3;toolbar:false">my_tuple = (1, 2, 3) print(len(my_tuple))  # 输出 3</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">查找元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 in 关键字来查找元素是否存在于元组中，如下所示：<pre class="brush:as3;toolbar:false">my_tuple = (1, 2, 3) print(2 in my_tuple)  # 输出 True</pre><p class="p3" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "PingFang SC"; white-space: normal;">以上是Python元组的常见操作，可以根据需要进行使用。由于元组是不可变的，因此它们比列表更适合用于存储不可变的数据，如常量、配置参数等。

详细介绍Python列表的相关操作

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python, python教程
20077 阅读

<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中的列表（list）是一种有序的数据结构，可以存储任何类型的数据，包括数字、字符串、对象等。下面是Python列表的相关操作：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">创建列表<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用方括号 [] 或 list() 函数来创建列表，如下所示：<pre class="brush:as3;toolbar:false">my_list = [] my_list = list() my_list = [1, 2, 3]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">访问列表元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用索引来访问列表中的元素，索引从0开始，如下所示：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">my_list = [1, 2, 3]<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">print(my_list[0])  # 输出 1<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">切片列表<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用切片来获取列表的子集，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3, 4, 5] print(my_list[1:3])  # 输出 [2, 3]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">修改列表元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用索引来修改列表中的元素，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3] my_list[0] = 0 print(my_list)  # 输出 [0, 2, 3]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">添加元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 append() 方法向列表末尾添加元素，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3] my_list.append(4) print(my_list)  # 输出 [1, 2, 3, 4]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">插入元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 insert() 方法在列表的任意位置插入元素，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3] my_list.insert(1, 4) print(my_list)  # 输出 [1, 4, 2, 3]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">删除元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 remove() 方法删除指定元素，或使用 pop() 方法删除指定位置的元素，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3] my_list.remove(2)  # 删除值为2的元素 print(my_list)  # 输出 [1, 3] my_list.pop(1)  # 删除索引为1的元素 print(my_list)  # 输出 [1]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">获取列表长度<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 len() 函数获取列表的长度，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3] print(len(my_list))  # 输出 3</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">查找元素<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用 in 关键字来查找元素是否存在于列表中，如下所示：<pre class="brush:as3;toolbar:false">my_list = [1, 2, 3] print(2 in my_list)  # 输出 True</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">以上是Python列表的常见操作，可以根据需要进行使用。列表是Python中最常用的数据结构之一，它们非常灵活，可用于各种用途，例如存储数据、迭代、排序等。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;">

详细介绍Python字符串的相关操作

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python, python教程
10826 阅读

<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python字符串是一种常用的数据类型，表示由一个或多个字符组成的有序序列。Python提供了许多操作来处理字符串，包括以下内容：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">创建字符串<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在Python中，可以使用单引号、双引号或三重引号来创建字符串。例如：<pre class="brush:as3;toolbar:false">string1 = 'hello' string2 = "world" string3 = """Hello, World!"""</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在三重引号中创建的字符串可以跨越多行，这在编写多行文本时很有用。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">访问字符串中的字符<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用索引来访问字符串中的字符。在Python中，字符串的索引从0开始。例如：<pre class="brush:as3;toolbar:false">string = "hello" print(string[0]) #输出"h" print(string[1]) #输出"e" print(string[-1]) #输出"o"</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在第二个示例中，我们使用负索引访问字符串中的最后一个字符。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">字符串切片<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">除了使用索引访问单个字符之外，还可以使用切片访问字符串的子字符串。切片由起始索引和结束索引组成，中间用冒号分隔。例如：<pre class="brush:as3;toolbar:false">string = "hello" print(string[1:3]) #输出"el"</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">切片操作返回从起始索引到结束索引之间的子字符串。如果省略了起始索引或结束索引，则将其替换为字符串的开头或结尾。例如：<pre class="brush:as3;toolbar:false">string = "hello" print(string[:3]) #输出"hel" print(string[1:]) #输出"ello" print(string[:]) #输出"hello"</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">字符串拼接<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用加号运算符将两个字符串拼接在一起。例如：<pre class="brush:as3;toolbar:false">string1 = "hello" string2 = "world" string3 = string1 + " " + string2 print(string3) #输出"hello world"</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">字符串重复<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用乘号运算符重复字符串。例如：<pre class="brush:as3;toolbar:false">string = "hello" print(string * 3) #输出"hellohellohello"</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">字符串长度<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用len()函数获取字符串的长度。例如：<pre class="brush:as3;toolbar:false">string = "hello" print(len(string)) #输出5</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">字符串查找和替换<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用find()函数在字符串中查找子字符串，并返回第一个匹配的位置。如果未找到子字符串，则返回-1。例如：<pre class="brush:as3;toolbar:false">string = "hello world" print(string.find("world")) #输出6 print(string.find("python")) #输出-1</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用replace()函数将字符串中的一个子字符串替换为另一个字符串。例如：<pre class="brush:as3;toolbar:false">string = "hello world" new_string = string.replace("world", "python") print(new_string) #输出"hello python"</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">字符串分割和连接<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用split()函数将字符串分割为子字符串列表。例如：<pre class="brush:as3;toolbar:false">string = "hello world" list = string.split(" ") print(list) #输出["hello", "world"]</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用join()函数将字符串列表连接为单个字符串。例如：<pre class="brush:as3;toolbar:false">list = ["hello", "world"] string = " ".join(list) print(string) #</pre><p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;">

详细介绍Python中的for循环语句

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python, python教程
10814 阅读

<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中的for循环语句是一种常用的迭代控制结构，它允许我们遍历任意序列（例如字符串、列表、元组等）中的每个元素，并对它们进行操作。for循环语句的一般形式如下：<pre class="brush:as3;toolbar:false">for 变量 in 序列:     循环体语句</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，变量表示序列中的每个元素，序列可以是任何可迭代对象，包括字符串、列表、元组、字典等。循环体语句是需要重复执行的代码块，它可以包含任意数量的语句，甚至可以嵌套其他的控制结构。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">下面我们逐一介绍for循环语句的各种应用：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">遍历序列<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">最常见的用途就是遍历序列，下面是一个遍历列表的例子：<pre class="brush:as3;toolbar:false">fruits = ["apple", "banana", "cherry"] for fruit in fruits:     print(fruit)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">这个例子中，我们定义了一个列表fruits，然后使用for循环遍历其中的每个元素，并将其打印出来。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">遍历字符串<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">由于字符串也是序列类型的对象，因此可以使用for循环遍历其中的每个字符：<pre class="brush:as3;toolbar:false">string = "hello, world!" for char in string:     print(char)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">这个例子中，我们遍历了一个字符串，将其中的每个字符逐一打印出来。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">遍历数字序列<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">可以使用range()函数生成一个数字序列，然后使用for循环遍历其中的每个数字。例如，下面的代码可以打印出0到4的所有整数：<pre class="brush:as3;toolbar:false">for i in range(5):     print(i)</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">嵌套循环<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">for循环还可以嵌套在其他的for循环或其他的控制结构中，以实现更加复杂的功能。例如，下面的代码可以打印出一个5x5的乘法表：<pre class="brush:as3;toolbar:false">for i in range(1, 6):     for j in range(1, 6):         print(i * j, end="\t")     print()</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在这个例子中，我们嵌套了两个for循环，一个用于遍历行，一个用于遍历列，然后在内层循环中打印每个元素，并在每行末尾添加一个换行符。外层循环在每行的末尾也打印一个换行符，以使下一行从新的一行开始。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;">

详细介绍Python中的while循环语句嵌套

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python, python教程
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<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中的while循环语句也是一种常用的迭代控制结构，它允许我们在满足某个条件时重复执行某段代码。while循环语句的一般形式如下：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">while 条件表达式:<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">    循环体语句<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">其中，条件表达式是一个返回布尔值的表达式，当它为True时，循环体语句会被执行。循环体语句可以包含任意数量的语句，甚至可以嵌套其他的控制结构。在每次循环执行完毕后，条件表达式会被重新计算，直到它变为False时循环才会终止。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">下面我们介绍while循环语句的嵌套应用：<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">嵌套while循环<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">while循环可以嵌套在其他的while循环或其他的控制结构中，以实现更加复杂的功能。例如，下面的代码可以打印出一个5x5的乘法表：<pre class="brush:as3;toolbar:false">i = 1 while i <= 5:     j = 1     while j <= 5:         print(i * j, end="\t")         j += 1     print()     i += 1</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在这个例子中，我们嵌套了两个while循环，一个用于遍历行，一个用于遍历列，然后在内层循环中打印每个元素，并在每行末尾添加一个制表符。外层循环在每行的末尾也打印一个换行符，以使下一行从新的一行开始。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">控制循环流程<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在循环执行过程中，有时需要使用break语句或continue语句来控制循环的流程。其中，break语句可以用于在循环中跳出整个循环，而continue语句可以用于跳过当前迭代并进入下一次迭代。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">下面是一个嵌套while循环中使用break和continue的例子：<pre class="brush:as3;toolbar:false">i = 1 while i <= 10:     if i == 5:         i += 1         continue     elif i == 8:         break     print(i)     i += 1</pre><p class="p3" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "PingFang SC"; white-space: normal;">在这个例子中，我们使用while循环从1到10遍历数字，但是当i等于5时，我们使用continue语句跳过当前迭代，进入下一次迭代；当i等于8时，我们使用break语句跳出整个循环。在每次循环执行完毕后，我们都打印出当前的i的值。注意，当i等于5时，我们不会打印任何值，因为这次循环被跳过了。

详细介绍Python中的if 嵌套

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python, python教程
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<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在Python中，if语句可以嵌套，允许在if语句块中嵌套其他if语句块。嵌套的if语句结构与单个if语句的结构类似，只是它们包含在其他if语句块中。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">下面是一个简单的if嵌套语句的例子：<pre class="brush:as3;toolbar:false">x = 10 y = 5 if x > y:     if x > 0:         print("x is positive and greater than y")     else:         print("x is negative") else:     print("x is less than or equal to y")</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在上面的例子中，我们首先检查x是否大于y。如果x大于y，则进入嵌套的if语句块。在嵌套的if语句块中，我们检查x是否大于0。如果是，则输出“x是正数且大于y”，否则输出“x是负数”。如果x小于或等于y，则不执行嵌套的if语句块，并输出“x小于或等于y”。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在Python中，可以嵌套多个if语句块，但是嵌套过多可能会导致代码难以理解和维护。因此，应该尽量避免过度嵌套if语句块，并考虑使用其他控制结构，例如循环或函数。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;">

详细介绍Python中elif 的使用

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python, python教程
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<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在Python中，elif是if语句的一个可选部分，可以用来测试多个条件。elif在if和else之间使用，用于测试前面的条件不满足时的另一种情况。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">以下是一个简单的示例，演示了如何使用elif：<pre class="brush:as3;toolbar:false">x = 10 y = 5 if x > y:     print("x is greater than y") elif x == y:     print("x is equal to y") else:     print("x is less than y")</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在上面的例子中，首先检查x是否大于y。如果是，则输出“x大于y”。如果x不大于y，则检查x是否等于y。如果x等于y，则输出“x等于y”。否则，输出“x小于y”。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">需要注意的是，在if-elif-else结构中，只有一个代码块会被执行。当if语句的条件为真时，if代码块将被执行，并且elif和else代码块都不会执行。如果if语句的条件为假，则检查下一个elif条件，如果为真，则执行elif代码块，否则继续检查下一个elif条件，直到找到一个为真的条件为止。如果所有的elif条件都为假，则执行else代码块。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">下面是另一个示例，演示如何在elif语句中测试多个条件：<pre class="brush:as3;toolbar:false">x = 10 y = 5 if x > 0 and y > 0:     print("Both x and y are positive") elif x > 0 or y > 0:     print("At least one of x and y is positive") else:     print("Neither x nor y is positive")</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">在上面的例子中，首先检查x和y是否都大于0。如果是，则输出“x和y都是正数”。如果不是，则检查x和y是否至少有一个大于0。如果至少有一个大于0，则输出“x和y中至少有一个正数”。否则，输出“x和y都不是正数”。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;">

python条件语句与循环语句

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python, python教程
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<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中的条件语句和循环语句是控制流程的重要组成部分，可以帮助我们实现不同的逻辑和算法。下面分别介绍一下Python中常见的条件语句和循环语句。<p class="p2" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; min-height: 17px; white-space: normal;"> <p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">条件语句<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中常见的条件语句包括if语句和if-else语句。if语句用于测试一个条件，如果条件为真则执行一段代码块，否则不执行。if-else语句在if语句的基础上增加了一个else分支，用于在条件为假时执行另一段代码块。<pre class="brush:as3;toolbar:false"># if语句示例 if x > y:     print("x is greater than y") # if-else语句示例 if x > y:     print("x is greater than y") else:     print("x is less than or equal to y")</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中还支持使用elif关键字来增加多个条件分支。elif语句在if语句和else语句之间使用，用于测试前面的条件不满足时的另一种情况。<pre class="brush:as3;toolbar:false"># if-elif-else语句示例 if x > y:     print("x is greater than y") elif x == y:     print("x is equal to y") else:     print("x is less than y")</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">循环语句<p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中常见的循环语句包括for循环和while循环。for循环用于遍历一个序列或迭代器中的元素，而while循环用于在条件为真时重复执行一段代码块。<pre class="brush:as3;toolbar:false"># for循环示例 for i in range(1, 11):     print(i) # while循环示例 x = 10 while x > 0:     print(x)     x -= 1</pre><p class="p1" style="margin-top: 0px; margin-bottom: 0px; font-variant-numeric: normal; font-variant-east-asian: normal; font-stretch: normal; font-size: 15px; line-height: normal; font-family: "Helvetica Neue"; white-space: normal;">Python中还支持使用break和continue关键字来控制循环的执行。break语句用于在循环中终止执行，而continue语句用于跳过当前迭代并继续执行下一次迭代。<pre class="brush:as3;toolbar:false"># break语句示例 for i in range(1, 11):     if i == 5:         break     print(i) # continue语句示例 for i in range(1, 11):     if i % 2 == 0:         continue     print(i)</pre>