1.条件判断
if 要判断的条件:
条件成立时,要做的事
age = 18
if age >= 18:
print('你已经成年了')
age = 12
if age >= 18:
print('你已经成年.')
else:
print('你未满18岁')
2.if语句嵌套
if 要判断的条件:
条件成立时,要做的事情
elif 条件2:
要做的事情
else:
条件不成立时,要做的时请
注意:elif和else都必须和if联合使用,不能单独使用
3.逻辑运算符
1)and
条件1 and 条件2
两个条件同时满足,就返回True
两个条件有一个不满足,就返回False
age=44
if age >= 0 and age <=120:
print('年龄正确')
else:
print('年龄错误')
2)or:
条件1 or 条件2
两个条件只要有一个满足,就返回True
两个条件都不满足,返回False
python_score = 61
c_score = 30
if python_score > 60 or c_score > 60:
print('考试通过')
else:
print('您未通过考试')
4.综合应用
1)石头剪刀布
import random #随机数模块导入
#1.输入要出的拳:石头=1 剪刀=2 布=3
player = int(input("请输入您要出的拳: 石头1/剪刀2/布3 :"))
#2.电脑随机出拳
computer = random.randint(1,3)
print(computer)
#3.比较胜负
if ((player == 1 and computer == 2)
or (player == 2 and computer == 3)
or (player == 3 and computer == 1)):
print('玩家胜利~')
elif player == computer:
print('平局')
else:
print('玩家失败~')
2)判断闰年
year = int(input("请输入您要判断的年份:"))
if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
print("%s年是闰年" %year)
else:
print("%s年不是闰年" %year)
3)输入年、月,输出本月有多少天
year = int(input("请输入一个年份:"))
month = int(input("请输入一个月份:"))
if month == 2:
if 0 == year % 400 or (0 == year % 4 and 0 != year % 100):
day = 29
print('%s年%s月有:%s天' % (year, month, day))
else:
day = 28
print('%s年%s月有:%s天' % (year, month, day))
elif month == 1 or month == 3 or month == 5 or month == 7 or month == 8 or month == 10 or month == 12:
day = 31
print('%s年%s月有:%s天' % (year, month, day))
elif month == 4 or month == 6 or month == 9 or month == 11:
day = 30
print('%s年%s月有:%s天' % (year, month, day))