Python的判断语句

Python的判断语句

比较

在Python中比较语句和其它的一样都是用if来做判断的，只是语法上后面会带上冒号，如if a>b:,相当于if（a>b）{}.

同样你可以判断函数的返回值为True或者False来做判断

__author__="Alex"
__date__ ="$2011-2-17 10:39:27$"
if __name__ == "__main__":
    print "Hello";
a = 3
b = 2
c = 2
# True statements
if c == b: print('c is equal as b')
if c >= b: print('...')
if a >= b: print('a is greater than b')
if c <= a: print('c is less than a.')
if c != a: print('c is not equal as a')
# False statements
if c == a: print('...')# will show nothing on console
if c != b: print('...')# will show nothing on console
def inside():
    return True
if inside():
    print ("Inside")
else:
    print("OutSide")

Console OutPut:

Hello
c is equal as b
...
a is greater than b
c is less than a.
c is not equal as a
Inside

多重比较：

当然你可能会用到 且或这些操作，在Python中是使用and/or 来做到的，看代码吧，从代码中学习语言才是王道:

__author__="Alex"
__date__ ="$2011-2-17 10:39:27$"
if __name__ == "__main__":
    print "Hello";
if 4 > 3 and 6 > 3: print('You are right , 4 is greater than 3 and 6 is greater than 3 too') # will print, True and True becomes True
if 4 > 3 and 2 > 3: print('...') # will not print, True and False becomes False
if 4 > 3 and not 2 > 3: print('You are right , 4 is greater than 3 and 2 is less than 3 ') # will print, True and not False becomes True
if 4 > 3 or 6 > 3: print('You are right...,When 4 is grater than 3 is ture, the condition is ture') # will print, True or True becomes True
if (4 > 3 and 6 > 3) and not ( 3 > 5 or 3 > 7): print("(True and True) and not ( False or False ) becomes True and not False")#Complex Multiple Conditions

Console Output:

Hello
You are right , 4 is greater than 3 and 6 is greater than 3 too
You are right , 4 is greater than 3 and 2 is less than 3
You are right...,When 4 is grater than 3 is ture, the condition is ture
(True and True) and not ( False or False ) becomes True and not False