[Course 5.3] Loop statement: for loop
The for loop can traverse any sequence of items, such as a list or a string.
Iterate
1. What if I want to output "hello world" 5 times?
for i in range(5):
print('hello world!')
-------------------------------------------------------------------
hello world!
hello world!
hello world!
hello world!
hello world!
2. Traverse the sequence and map by for
lst = list(range(10))
for i in lst[::2]:
print(i)
print('-----')
# 遍历list
age = {'Tom':18, 'Jack':19, 'Alex':17, 'Mary':20}
for name in age:
print(name + '年龄为：%s岁' % age[name])
# 遍历字典
-------------------------------------------------------------------
0
2
4
6
8
-----
Mary年龄为：20岁
Tom年龄为：18岁
Alex年龄为：17岁
Jack年龄为：19岁
3. Nested loop
for i in range(3):
for j in range(2):
print(i,j)
# 循环套循环，注意：尽量不要多于3个嵌套
-------------------------------------------------------------------
0 0
0 1
1 0
1 1
2 0
2 1
