python对常见数据类型的遍历解析

> a_str = "hello itcast"
> for char in a_str:
...   print(char,end=' ')
...
h e l l o  i t c a s t

> a_list = [1, 2, 3, 4, 5]
> for num in a_list:
...   print(num,end=' ')
...
1 2 3 4 5

> a_turple = (1, 2, 3, 4, 5)
> for num in a_turple:
...   print(num,end=" ")
1 2 3 4 5

> a_dict = {"name":"lxy","sex":"男","age":18}
> for key in a_dict.keys():
  print(key)  
name
sex
age

> a_dict = {"name":"lxy","sex":"男","age":18}
> for value in a_dict.values():
  print(value)
lxy
男
18
> 

> a_dict = {"name":"lxy","sex":"男","age":18}
> for key,value in a_dict.items():
  print("key=%s,value=%s"%(key,value))  
key=name,value=lxy
key=sex,value=男
key=age,value=18

> chars = ['a', 'b', 'c', 'd']
> i = 0
> for chr in chars:
...   print("%d %s"%(i, chr))
...   i += 1
...
0 a
1 b
2 c
3 d

> chars = ['a', 'b', 'c', 'd']
> for i, chr in enumerate(chars):
  print(i,chr) 
0 a
1 b
2 c
3 d
>