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python的列表(二)

1、遍历整个列表

 #for 循环 #

>>> name_list
[‘faker‘, ‘dopa‘, ‘gogoing‘, ‘uzi‘]  
>>> for LOL_Player in name_list:
... print(LOL_Player)
faker
dopa
gogoing
uzi

第一步,定义一个列表*name_list*

第二步,通过for语句遍历列表,结果存放到字符串LOL_Player

第三步,打印字符串

for 循环遍历的结果是把整个list中的所有元素读取出来,并且按元素换行。

 

2,在for循环中执行更多的操作

#在for循环中可以对每一个元素都可以执行任何操作#

>>> name_list
[‘faker‘, ‘dopa‘, ‘gogoing‘, ‘uzi‘]
>>> for LOL_Player in name_list:
... print(LOL_Player.title() + ", They are great players")
...
Faker, They are great players
Dopa, They are great players
Gogoing, They are great players
Uzi, They are great players

3,在for循环结束后执行一些操作

在for循环后面,没有缩进的代码都只执行一次,而且不会重复执行。

name_list=[‘faker‘,‘dade‘,‘gogoing‘,‘clearlove7‘,‘cool‘]
for LOL_Player in name_list:
print(LOL_Player.title() +", They are great players")
print("Thank you, everyone.")

[root@albenlinux Learn-python]# ./for.py
Faker, They are great players
Dade, They are great players
Gogoing, They are great players
Clearlove7, They are great players
Cool, They are great players
Thank you, everyone.

4,创建数值列表

 函数range()

>>> for value in range(1,5):
... print(value)
...
1
2
3
4

要想创建数字列表,只需要通过list()把range()的结果直接转换为列表

例如:

设置一个列表,叫做numbers,其中包含元素[1,2,3,4,5]

>>> numbers=list(range(1,6))
>>> print(numbers)
[1, 2, 3, 4, 5]

使用range()的时候,还可是设置步长:

 

>>> numbers_even=list(range(0,11,2))
>>> numbers_even
[0, 2, 4, 6, 8, 10]

 

将指定整数的平方赋值到变量中

 

>>> squares=[]
>>> for value in range(1,11):
          squares.append(value**2)
>>> squares
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

 

#这里使用了for遍历,让每一个元素都进行**2(在python中**2代表平方),把每个元素的平方追加到列表中

对列表执行简单的统计:

>>> squares
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
>>> min(squares)
1
>>> max(squares)
100
>>> sum(squares)
385

列表解析:

通过一行代码,生成上面的squares.py文件

>>> squares=[value**2 for value in range(1,11)]
>>> squares
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

使用列表的一部分:

1,切片

>>> lol_players
[‘faker‘, ‘dopa‘, ‘cool‘, ‘dade‘, ‘clearlove7‘, ‘amazingj‘, ‘smlz‘]
>>> print(lol_players[0:3])
[‘faker‘, ‘dopa‘, ‘cool‘]

#切片其实和range()函数相同,指定索引(0:3)其实就是切了元素0,1,2(记得python的index是从0开始的)#

切片也可以指定步长,不如给一个列表包含数字0-10,进行切片,步长=3

 

>>> number=list(range(0,11))
>>> number
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> print(number[0:11:3])
[0, 3, 6, 9]


遍历切片:

lol_players
[‘faker‘, ‘dopa‘, ‘cool‘, ‘dade‘, ‘clearlove7‘, ‘amazingj‘, ‘smlz‘]

>>> for head_3_players in lol_players[0:3]:
... print(head_3_players.title())
...
Faker
Dopa
Cool

 

python的列表(二)