substring：要查找的子字符串。start（可选）：开始查找的起始位置，默认为 0。end（可选）：结束查找的位置，默认为字符串的长度。示例：1. 查找子字符串：text = "Hello, world! This is an example."# 使用 find 查找子字符串index = text.find("world")print("Index of 'world':", index) # 输出...
deffind_substrings(string,substrings):positions=[]forsubstringinsubstrings:index=string.find(substring)positions.append(index)returnpositions# 示例用法string="This is a test string."substrings=["is","test","string"]positions=find_substrings(string,substrings)print(positions)# 输出:[2, 10, 17] ...
下面是将以上四个步骤整合在一起的完整代码示例: defindex_of_substring(string,substring):string_list=list(string)forindex,charinenumerate(string_list):ifchar==substring[0]:# 判断当前字符是否与子字符串的第一个字符相同ifstring[index:index+len(substring)]==substring:# 判断当前字符后续字符是否与子字符...
Write a Python program to determine the index of a given string at which a certain substring starts. If the substring is not found in the given string return 'Not found'. Sample Solution: Python Code: # Function to find index of substring def find_Index(str1, pos): # Check if pos lo...
Python String find() The find() method returns the lowest index of the substring if it is found in given string. If its is not found then it returns -1. Syntax : str.find(sub,start,end) Parameters : sub :It’s the substring which needs to be searched in the given string....
# find the index of isresult = text.index('is') print(result)# Output: 7 index() Syntax It's syntax is: str.index(sub[, start[, end]] ) index() Parameters Theindex()method takes three parameters: sub- substring to be searched in the stringstr. ...
The index method can’t return a number because the substring isn’t there, so we get a value error instead: In order to avoid thisTraceback Error, we can use the keywordinto check if a substring is contained in a string. In the case of Loops, it was used for iteration, whereas in...
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 ...
in <module>ValueError: substring not found从Python手册string.find(s, sub[, start[, end]])返回s...
今天给大家说下python字符串的find方法,从python的文档里可以知道find方法是查找子串在字符串的开始位置。 看下文档解释: string.find(s, sub[, start[, end]]) Return the lowest index in s where the substring sub is found such that sub is wholly contained in s[start:end]. Return -1 on failure...