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Python中if语句的用法

Python中if语句的用法

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Python中if语句的用法

if语句是各类语言的基础语句,在python中是通过一条或多条语句的执行结果(True或者False)来决定执行的代码块,今天给大家分享一下Python中的IF语句的使用场景以及注意事项。

基本构成:

if 条件彩良欠:    

if语句块  

else:      

else语句

用于比较运算(大于>)中:

a = 0

if a > 0:

print "a is not 0"

else:

print 'a is o'

用于比较运算中结合逻辑运算符:

a = 50

if a< 100 and a > 10:

print "a is not 0"

else:

print 'a is false'

and的优先级大于or有括号的运算最优先:

a = 50

if (a< 100 and a > 10 or (a >20 and a<100):

print "a is true"

else:

print 'a is false'

结合比较运算操作符: >< == >= <= == != <>:

a =90

b =100

if a>b:

print "a is max"

else:

print 'a is min'

结合不等宿囊于实例:

a =90

b =100

if a<>b:

print "a is max"

else:

print 'a is min'

结合成员关系运算符:In (not in ):

name = 'zhangshan'

if 'zhang' not in name:

print 'zhang is in name'

else:

print 'zhang is not in name'

elif嵌套结构:

if 条件:

if语句块

elif 条件:

elif语句块

else:

else语句块

用于检查多个条件是否满足:

number1 = int(input("请输入数字1:"))

number2 = int(input("请输入数字2:"))

if number1 > number2:

print "{} 大于 {}".format(number1,number2)

elif number2 < number2:

print "{} 小于 {}".format(number1,number2)

elif number1 == number2:

print '%s 等于 %s'%(number1,number2)

else:

print '婶绵game is over'

嵌套语句2:

name = input("请输入信息:")

if name.endswith('hello'):

if name.startswith('china'):

print 'welcome to {}'.format(name)

elif name.startswith('japan'):

print 'say you {}'.format(name)

else:

print '输入有误,重新输入'

else:

print '游戏结束---->'