示例

# -*- coding: cp936 -*-
print '条件和条件语句'
#下面的值会被解释器看作假(false)
#False、None、0、""、()、[]、{}

#显示转换布尔值
print bool('I think, therefore I am')

#if语句
#短路逻辑(惰性求值),类似三元运算.
#如果raw_input()返回假(即,空字符串),则执行or后面的
name = raw_input('What is your name? ') or '<unknown>'
if name.endswith('Gumby'):
    print 'Hello. Mr. Gumby'
elif name.endswith('aaa'):
    print 'Hello, aaa'
else:
    print 'Hello, ' + name

num = input('Enter a number: ')
#或者
#num = int(raw_input('Enter a number: '))
if num > 0:
    print 'The number is positive'
elif num < 0:
    print 'The number is negative'
else:
    print 'The number is zero'

#比较运算符可以连接使用
age = 42
if 0 < age < 100:
    print 'age'

a = 'a'
b = True
c = 'c'
#如果b为Ture返回a, 否则返回c
d = a if b else c
print d

#布尔运算符 and、or、not

print '断言'
age = -1
assert 0 < age < 100, 'The age must be realistic'

运行测试