循环结构
应用场景
- 持续打印某一相同的话
- LED屏上持续滚动的字
for-in循环
明确知道循环次数或者对一个容器进行迭代
'''
1--100求和
'''
sum = 0
for i in range(101):
sum += i
print(sum)
'''
1--100之间的偶数和
'''
sum = 0
for i in range(2,101,2):
sum += i
print(sum)
while循环
不知道循环次数利用while循环
'''
猜数字游戏(1--100)
'''
from random import randint
answer = randint(1,100)
count = 0
while True:
count += 1
num = int(input("请输入您猜测的数字:"))
if num == answer:
print("bingo,您真厉害!")
break
elif num > answer:
print("大了一点点")
else:
print("小了一点点")
print("你总共猜了%d次" % count)
'''
九九乘法表
'''
for i in range(1, 10):
for j in range(1, i+1):
print("%d*%d=%d" % (i, j, i*j),end='\t')
print()
练习
输入一个数判断是不是素数
import math
num = int(input("请输入一个整数:"))
is_prim = 0
for i in range(2, math.sqrt(num) + 1):
if num % i == 0:
is_prim = 1
break
if is_prim and num != 1:
print("不是素数")
else:
print("是素数")
输入两个正整数,计算最大公约数和最小公倍数
num1 = int(input("请输入第一个数:"))
num2 = int(input("请输入第二个数:"))
if num1 > num2:
num1, num2 = num2, num1
for i in range(num1, 0, -1):
if num1 % i == 0 and num2 % y == 0:
print("最大公约数为:%d" % i)
print("最小公倍数为:%d" % (num1*num2//i))
break
打印三角形
打印上三角,正三角,下三角
row = int(input("请输入要打印的行数:"))
for i in range(row):
for j in range(i+1):
print("*",end="")
print()
for i in range(row):
for j in range(row):
if j < row - i - 1:
print(" ",end = "")
else:
print("*",end = '')
print()
for i in range(row):
for j in range(row - i - 1):
print(" ",end='')
for j in range(2*i+1):
print("*",end='')
print()