使用range()和不在for循环中使用它有什么区别？

Question

我有这个:

colors = ["blue","brown","red","yellow","green"]

1.

for color in colors:

2.

for index in range(len(colors)):

使用1和2有什么区别？

Answer 1

当您说for color in colors:您正在迭代列表中的项目时.

for color in colors:
    print(color)

>>> "blue"
>>> "brown"
>>> "red"
>>> "yellow"
>>> "green"

如果你迭代索引,你得到:

for index in range(len(colors)):
    print(index)

>>> 0
>>> 1
>>> 2
>>> 3
>>> 4

您可以使用enumerate以下方法将两个版本放在一起:

for c, color in enumerate(colors):
    print(c, color)

>>> 0 "blue"
>>> 1 "brown"
>>> 2 "red"
>>> 3 "yellow"
>>> 4 "green"