python判断字符是否存在

使用成员操作符 in

>>>s='nihao,shijie'
>>>t='nihao'
>>>result=tins
>>>printresult
True

使用string模块的find()/rfind()方法

>>>importstring
>>>s='nihao,shijie'
>>>t='nihao'
>>>result=string.find(s,t)!=-1
>>>printresult
True
>>>result=string.rfind(s,t)!=-1
>>>printresult
True

使用string模块的index()/rindex()方法

index()/rindex()方法跟find()/rfind()方法一样，只不过找不到子字符串的时候会报一个ValueError异常。

importstring
deffind_string(s,t):
try:
string.index(s,t)
returnTrue
except(ValueError):
returnFalse
s='nihao,shijie'
t='nihao'
result=find_string(s,t)
printresult#True

>>>s='nihao,shijie'
>>>t='nihao'
>>>result=s.find(t)>=0
>>>printresult
True
>>>result=s.count(t)>0
>>>printresult
True
>>>result=s.index(t)>=0
>>>printresult
True