与find()方法不同的是,index()方法在找不到子字符串时会抛出ValueError异常,因此需要进行异常处理。 AI检测代码解析 deffind_all_positions(string,substring):positions=[]start=0try:whileTrue:position=string.index(substring,start)positions.append(position)start=position+1exceptValueError:passreturnpositions strin...
Theindexmethod in particular, returns the index of the given substring, inside the string.The substring that we pass, can be as long or as short as we want.And what happens if the string doesn’t have the substring we’re looking for?The index method can’t return a number because the...
def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__ """ S.find(sub[, start[, end]]) -> int Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are ...
If substring exists inside the string, it returns the lowest index in the string where substring is found. If substring doesn't exist inside the string, it raises aValueErrorexception. Theindex()method is similar to thefind()method for strings. The only difference is thatfind()method returns-...
下面是一个完整的示例,结合了find()、index()和正则表达式的方法,实现了子串在字符串中出现的所有位置的查找: importredeffind_substring_positions(str,sub):positions=[]start=0whileTrue:index=str.find(sub,start)ifindex==-1:breakpositions.append(index)start=index+1returnpositionsdefindex_substring_positions...
index('or', 9)) # ValueError: substring not found 说明:find方法找不到指定的字符串会返回-1,index方法找不到指定的字符串会引发ValueError错误。 find和index方法还有逆向查找(从后向前查找)的版本,分别是rfind和rindex,代码如下所示。 s = 'hello world!' print(s.find('o')) # 4 print(s.rfind('...
find() Return Value Thefind()method returns an integer value: If the substring exists inside the string, it returns the index of the first occurence of the substring. If a substring doesn't exist inside the string, it returns-1. Working of find() method ...
print( str.index('wo') ) # 'wc'不在字符串中,程序报错ValueError,终止运行 print( str.index('wc') ) ## 输出: ## 6 ## ValueError: substring not found count() (https://jq.qq.com/?_wv=1027&k=SX0QxtkE) 功能: 返回str1在string中指定索引范围内[start, end)出现的次数。
| Return the lowest indexinS where substring subisfound,| such that subiscontained within s[start:end]. Optional| arguments startandend are interpreted asinslice notation.| | Return -1 on failure 假定S为string类型的对象,调用find函数,将子串或子串的子串(也就是子串从start到end的切片)作为参数传...
if s.find('Name') != -1: print('Substring found') Note that find() function returns the index position of the substring if it’s found, otherwise it returns -1. Count of Substring Occurrence We can usecount() functionto find the number of occurrences of a substring in the string. ...