python之列表(List)介绍与循环遍历

2025-11-06 14:29:05

1、创建列表:

In [13]: list1=[123,34,56]In [14]: list2=["zhang","qing",'hahah']In [15]: list3=["zhang",123,"qing",234]In [16]: list4=["zhang123","123zhang",123,344]In [17]: list5=["zhang123",1123,123zhang]  File "<ipython-input-17-f6f00b6fdc24>", line 1    list5=["zhang123",1123,123zhang]                                  ^SyntaxError: invalid syntax使用中括号,且用逗号把不同的数据分开即可。

python之列表(List)介绍与循环遍历

2、列表中的值:

列表之格式:str=['zhang','chong',12,34]

使用下标索引访问列表中的值,以0开始。

例如:

In [49]: str1=["123","zhang","123zhang",123,345]

In [50]: str1

Out[50]: ['123', 'zhang', '123zhang', 123, 345]

In [51]: str1[0]

Out[51]: '123'

In [52]: str1[1]

Out[52]: 'zhang'

In [53]: str1[-1]

Out[53]: 345

In [54]: str1[-2]

Out[54]: 123

python之列表(List)介绍与循环遍历

3、根据前面的学习,大家知道字符串是不能够被修改的,所以依据字符串创建列表是很有必要的

比如:

In [18]: list("zhang qing")Out[18]: ['z', 'h', 'a', 'n', 'g', ' ', 'q', 'i', 'n', 'g']In [19]: list('zhanghahah')Out[19]: ['z', 'h', 'a', 'n', 'g', 'h', 'a', 'h', 'a', 'h']In [20]: list(zhang)---------------------------------------------------------------------------NameError                                 Traceback (most recent call last)<ipython-input-20-dfd76f282fd1> in <module>()----> 1 list(zhang)NameError: name 'zhang' is not defined

python之列表(List)介绍与循环遍历

4、循环遍历之for循环

===》为了更有效率的输出列表的每个数据,可以使用循环来完成

示例:

In [3]: list1=["zhang","qing","123",123,"zhang123"In [4]: for temp in list1:

   ...:     print("遍历list1=%s"%temp)

   ...:     遍历list1=zhang

遍历list1=qing

遍历list1=123

遍历list1=123

遍历list1=zhang12

python之列表(List)介绍与循环遍历

5、注意:不合法示例如下:

In [5]: for temp in list1:

   ...:     print(list1[temp])

   ...:    

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-5-84f18180053e> in <module>()

      1 for temp in list1:

----> 2     print(list1[temp])

      3TypeError: list indices must be integers or slices, not str

python之列表(List)介绍与循环遍历

6、循环之while:

为了更有效率的输出列表的每个数据,可以使用循环来完成

In [9]: list1=["zhang","qing","123",345In [10]: i=0

In [11]: while i<len(list1):

   ....:     print(list1[i])

   ....:     i+=1

   ....:    

zhang

qing

123

345

python之列表(List)介绍与循环遍历

7、注意:

In [6]: list1=["zhang","qing",'123',345]

In [7]: i=0

In [8]: while i<=len(list1):

   ...:     print(list1[i])

   ...:     i+=1

   ...:     zhang

qing

123

345

---------------------------------------------------------------------------IndexError                                Traceback (most recent call last)

<ipython-input-8-6410fdf10b12> in <module>()

      1 while i<=len(list1):

----> 2     print(list1[i])

      3     i+=1

      4IndexError: list index out of range

python之列表(List)介绍与循环遍历

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