python中for循环变量作用域及用法详解

def foo():
  return [lambda x: x**i for i in range(1,5,2)]
print([f(3) for f in foo()])

def foo():
  functions=[]
  for i in range(1,5,2):
    def inside_fun(x):
      return x ** i
    functions.append(inside_fun)
  return functions
print([f(3) for f in foo()])

def foo():
  i=None
  for i in range(1,5,2):
    pass
  print(i)
foo() # 结果为3，即循环结束i的最终值

#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