python 循环

while循环
# 使用while循环实现0 -10 相加

 i = 1
 sum = 0
 while i <=100 :
     sum = sum +i
     print(sum)

    i += 1
'''
第一次循环i = 1,sum = 0,--> sum = sum + i = 1+ 0 = 1 ,sum=1,i=2
第二次循环i = 2,sum = 1,--> sum = sum + i = 2+ 1 = 3 ,sum=3,i=3
第三次循环i = 3,sum = 2,--> sum = sum + i = 3+ 2 = 3 ,sum=6,i=4
.....
第九十九次循环 i = 99,sum = 4851,--> sum = sum + i = 4851+ 99 = 4950 ,sum=4950,i=100
第一百次循环 i = 100,sum = 4950,--> sum = sum + i = 4950+ 100 = 4950 ,sum=5050,i=101
第一百零一次循环 i = 101 ，不满组条件退出循环
'''

'''
将0 - 100 所有3的倍数相加
'''

i = 1
sum = 0
while i <= 100:
    if i % 3 == 0:
        sum += i
else:
    i += 1
print(sum)


i = 1
sum = 0
while i <= 100:
    if i % 3 == 0 or i // 10 == 3 or i //100 ==3:

        sum += i
else:
    i += 1
print(sum)

braek 终止循环
#吃四个苹果
i = 1
while i <= 4:
    print(f'吃第{i}个苹果')
    i += 1
print('===============================')

#吃四个苹果 吃到了第三个我就饱了 不用吃第四个了
i=1
while i <= 4:
  if i == 3:
    print(f'吃第{i}个苹果')
    print('我吃饱了，来喝口汤，怎么不喝啊')
    # 终止所有循环  跳出循环
    break
  i += 1

print('============================')

continue 循环

# 第三个循环 吃到一个带有半截虫子的苹果 跳出循环 继续吃第四个苹果 第三个苹果
i=0
while i < 4:
  i += 1
  if  i ==3 :
    print('这个苹果有半截虫子，不吃了')
    continue
  print(f'吃第{i}个苹果')

#  break和continue区别， break是终止所有循环，continue是跳出本次循环


for 循环

# 循环打印puthon每个单词
#       012345
str1 = 'python'

# i是临时变量 ，用来取值
for i in str1:
    print(i)

print('==============================')
'''
1 使用while循环取出y和o，打印出来
'''

j = 0
while j <6 :
    if j == 1 or j == 4:
        print(str1[j])
    j += 1
print('======================')

# 使用for循环打印 lames 跳过m

for i in 'james':
    if i == 'm':
        continue
    print(i,end=' ')

range的用法

for i in range(1, 6):
    print('*' * i)

print('================')
j = 2
for i in range(1, 6):
    if i % 2 == 1:
     print('*' * i)