'''
and 并且
or 或者
'''
colors =['red','blue','black','green']for color in colors:if color =='black':print('black')else:print('not black')
out:
not black
not black
black
not black
for color in colors:if color =='black':break# 跳出大循环print('black')else:print('not black')
out:not black
not black
for color in colors:if color =='black':continue# 跳出当前循环print('black')else:print('not black')
out:not black
not black
not black
if'red'in colors:#判断列表中是否有‘red’,返回值是true/falseprint('red')
out:red
null =[]if null:#判断列表是否为空,有值返回true,空的话返回falseprint(1)else:print(0)
out:0#if可以判断字符串的大小if'ann'<'bgg':print(1)else:print(0)