for in 用于遍历字符串、列表，元组，字典等

数组遍历

arr=['a','b','c']
for x in arr:
    print(x)

for i, v in enumerate(arr):
    print(i, v)

json数组遍历

arr=[{key:val},{..}]
for o in arr:
    print(o)  #{key:val}

json遍历

arr={key:val}
for k,v in arr.items():
    print(k,v)

for k in arr:
    print(k,arr.get(k))

for i=1 to 10

for i in range(10)
    print(i)

for i in range(5,10):
    print(i)

for in

for ch in 'Python': 
   print '当前字母 :', ch

for in 数组

https://blog.csdn.net/weixin_40522801/article/details/106172470

arr = ['banana', 'apple',  'mango']
for item in arr:
   print '当前 :', item

#for...in range() 

#for...in enumerate() 、for...in() 、

#for...in zip()

range

arr = ['banana', 'apple',  'mango']
for index in range(len(arr)):
   print '当前 :', arr[index]

for … else 表示这样的意思，for 中的语句和普通的没有区别，else 中的语句会在循环正常执行完（即 for 不是通过 break 跳出而中断的）的情况下执行，while … else 也是一样

for num in range(5,10): 
    if num%2 == 0:
        break
    print(num)
else:
    print()

for数组跳过第一个

for i in arr[1:]
    print(i)

#跳过最后一个元素
for i in arr[:-1]
    print(i)

for 对象跳过第一个元素

jsn=iter({"key":"val","key1":"val1"})
it=iter(jsn)
next(it) 
for xx in it:
    print(xx)