string="Hello, world!"position=string.find("o")print(position)# 输出 4 1. 2. 3. index()方法 index()方法与find()方法类似,但是如果找不到该字符或子字符串,则会抛出ValueError异常。 string="Hello, world!"position=string.index("o")print(position)# 输出 4 1. 2. 3. count()方法 count()...
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。 deffind_all_positions(string,substring):positions=[]start=0try:whileTrue:position=string.index(substring,start)positions.append(position)start=position+1exceptValueError:passreturnpositions string="Hello, Worl...
import res = "The quick brown fox jumps over the lazy dog."# 使用正则表达式查找单词 "fox"match = re.search(r"\bfox\b", s)if match: print(f"Found 'fox' at position {match.start()}") # 输出：Found 'fox' at position ¾# 查找所有以 "the" 开头的单词matches = re.findall(...
Strings can beconcatenatedto build longer strings using the plus sign and also they can bemultipliedby a number, which results in the continuous repetition of the string as many times as the number indicates. Also, if we want to find out thelengthof the string, we simply have to use thelen...
Character binstringabcdefispresent at2No such charater availableinstringxyze 方法#3:Using index() 如果字符不存在,则此方法引发ValueError # Python3 code to demonstrate # to find first position of character #ina givenstring# Initialisingstringini_string1='xyze'# Character to find ...
myString.find('x')-1使用 index()>>> myString = 'Position of a character'>>> myString....
Theindex()method is used to find the index of the first occurrence of a specified element in a list. This method is particularly useful when you need to know the position of a specific element within a list. Here’s an example of how to use theindex()method to find the index of the...
字符串查找功能str.find s1='ni hao, nice to Meet You' position=s1.find('A') # -1 表示没有找到 print(position) position=s1.find('M') print(position) #指定起始位置find position=s1.find('n', 2,9) print(position) #Str.find(str, beg=0, end=len(string)) #包头不包尾,查找范围是...
string.index(str, beg=0, end=len(string))跟find()方法一样,只不过如果str不在 string中会报一个异常. 代码语言:javascript 代码运行次数:0 运行 AI代码解释 >>>mystr.index("how")12>>>mystr.index("how",20,30)Traceback(most recent call last):File"<stdin>",line1,in<module>ValueError:subst...
str.find(sub,start,end) Parameters : sub :It’s the substring which needs to be searched in the given string. start :Starting position where sub is needs to be checked within the string. end :Ending position where suffix is needs to be checked within the string. ...