python中for循环的用法

Python for循环可以遍历任何序列的项目，如一个列表或者一个字符串。

语法模式：for iterating_var in sequence:

in 字面意思，从某个集合（列表等）里顺次取值

#遍历数字序列
the_count=[1,2,3,4,5]
for number in the_count:
    print(f"This is count {number}")

输出结果：

This is count 1
This is count 2
This is count 3
This is count 4
This is count 5

#遍历一维字符串数组
fruits=['apples','oranges','dimes','quarters']
for fruit in fruits:
    print(f"A fruit of type:{fruit}")

输出结果为：

A fruit of type:apples
A fruit of type:oranges
A fruit of type:dimes
A fruit of type:quarters

#遍历字符串
list_python='python'
for j in list_python:
    print(f"{j}")
输出结果为：

p
y
t
h
o
n

#通过序列索引迭代
elements=[]#列表为空
for i in range(0,6):#012345
    print(f"Adding {i} to the list.")

    elements.append(i)#得到elements=[0,1,2,3,4,5]

    #len(elements)长为6，range(len(elements))==range(6)
for i in range(len(elements)):
    print(f"Elemnet was:{i}")

输出结果为：

Adding 0 to the list.
Adding 1 to the list.
Adding 2 to the list.
Adding 3 to the list.
Adding 4 to the list.
Adding 5 to the list.
Elemnet was:0
Elemnet was:1
Elemnet was:2
Elemnet was:3
Elemnet was:4
Elemnet was:5