if...else...：
# -*- coding: utf-8 -*-
a = input("age:")
age = int(a)
if a:
if age > 1000:
print("神仙")
elif age > 100:
print("长寿")
else:
print("凡人")
else:
print("年龄为空")
image.png
for...in...：
#计算0到9的和
sum = 0
for x in range(10):
sum += x
print(sum)
while:
#计算0到9的和
sum = 0
n = 9
while n > 0:
sum += n
n -= 1
print(sum)
break和continue：
break跳出循环，continue跳出此次循环进入下一次循环，都要配合if用。
sum = 0
n = 9
while n > 0:
n -= 1
if n % 2 == 0:
sum += n
continue
print(sum) ----------------> 20
sum = 0
n = 9
while n > 0:
n -= 1
if n % 2 == 0:
sum += n
break
print(sum) ----------------> 8
