Python判断字符串是否包含子串

1.使用成员操作符 in

>>> s='nihao,shijie'
>>> t='nihao'
>>> result = t in s
>>> print result
True

2.使用string模块的find()/rfind()方法

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

3.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。

import string

def find_string(s,t):
    try:
        string.index(s,t)
        return True
    except(ValueError): 
        return False

s='nihao,shijie'
t='nihao'
result = find_string(s,t)
print result  #True

4.使用字符串对象的find()/rfind()、index()/rindex()和count()方法

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