Day -9 while与for

while 常见用法如下：

//while 
count = 1
while count<=5:
  print(count)
  count += 1

// result 
1
2
3
4
5

//while break 
count = 1
while count != 6:
  print(count)
  count += 1
  if count > 5:
    break

//result
1
2
3
4
5


//while break continue     
count = 0
while count != 6:
  if count > 5:
    break
  count += 1
  if count % 2 == 0:
    continue
  print(count)

//result
1
3
5 

// while break continue & if else  
guess_me = 7
number = 1
while True:
  if number < guess_me:
    print('too low')
  elif number == guess_me:
    print('found it!')
    break
  else:
    print('oops')
    break
  number += 1
  
// result

too low
too low
too low
too low
too low
too low
found it!

guess_me = 7
for number in range(10):
  if number < guess_me:
    print('too low')
  elif number == guess_me:
    print('found it!')
    break
  else:
    print('oops')
    break
    
// result
too low
too low
too low
too low
too low
too low
too low
found it!

同样的 guess_me = 7 for 会多显示一次too low，其他常见for用法。

a =["A", "B", "C", "D", "E"]
for num in a:
  print(num)
  
// result
A
B
C
D
E
  
for num in range(10,0,-1):
  print(num)
 
// result
10
9
8
7
6
5
4
3
2
1

a = [0,9,2,2]
for num in a:
  print(num)
  
// result 
0
9
2
2

• range(10) # 0 到10

0 1 2 3 4 5 6 7 8 9

• 1, 11 # 1 到 11

1 2 3 4 5 6 7 8 9 10

• range(0, 30, 5) # 每个值相差5

0  5 10 15 20 25