Python循环语句

1 while循环的基础语法

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

2 while循环的基础案例

案例1

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

案例2

import random
num = random.randint(1,100)
count = 0
flag = True
while flag:
    guess_num = int(input("请输入数字"))
    count += 1
    if guess_num == num:
        print("你猜中了")
        flag = False
    else:
        if guess_num < num:
            print("你猜小了")
        else:
            print("你猜大了")
print(f"你一共猜了{count}次")

3 while循环的嵌套应用

while嵌套循环的基本格式

while嵌套循环的应用

i = 1
while i <= 100:
    print(f"今天是第{i}天，准备表白")

    j = 1
    while j <= 10:
        print(f"送给小明{j}朵玫瑰")
        j += 1

    print("小明我喜欢你")
    i += 1

print(f"坚持到第{i-1}天，表白成功")

4 while循环的嵌套案例

i = 1
while i <=9:
    j = 1
    while j <= i:
        print(f"{j} * {i} = {j * i}\t",end="")
        j += 1
    i += 1
    print()

5 for循环的基础语法

基础语法

name = "itheima"
for i in name:
    print(i)

案例

name = "itheima is a brand of itcast"
count = 0
for i in name:
    if i == 'a':
        count += 1
print(count)

range语句

变量作用域

6 for循环的嵌套案例

i = 0
for i in range(1,100):
    print(f"今天是向小明表白的第{i}天")
    for j in range(1,11):
        print(f"给小明的第{j}朵花")
    print(f"第{i}天，表白成功")
print("小明我喜欢你")

for i in range(1,10):
    for j in range(1,i+1):
        print(f"{j} * {i} = {j * i}\t",end='')
    print()

7 循环中断：break和continue

continue

break