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...
接下来,我们需要使用字符串的find()方法来查找子串在字符串中的位置。find()方法会返回子串在字符串中第一次出现的索引,如果找不到,则返回-1。代码如下: # 查找子串在字符串中的位置position=string.find(substring) 1. 2. 这段代码使用find()方法查找子串substring在字符串string中的位置,并将结果赋值给变量pos...
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. s = 'My Name is Pankaj' print('Substring count =', s...
find()回报-1 和index()加薪ValueError。使用 find()>>> myString = 'Position of a character'>>...
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. ...
my_string = "Python" substring = my_string[1:4] print(substring) 3. 字符串的常用方法 3.1 字符串的查找 使用find() 方法查找子串在字符串中的位置。 my_string = "Hello, World!" position = my_string.find("World") print(position) 3.2 字符串的替换 使用replace() 方法替换字符串中的子串...
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 this case it’s a conditional that can be eithertrueorfalse.It’ll be true if the substring is part of the...
print("The position of Tutorials using index() : ", mystring.index("test")) ValueError: substring not found 在上面的示例中,我们试图找到子字符串“ test”的位置。 子字符串不存在于给定的字符串中,因此使用find()时,位置为-1,但是对于index(),它会引发如上所示的错误。
With optional end, stop comparing S at that position. suffix can also be a tuple of strings to try. """ return False def expandtabs(self, tabsize=None): """将tab转换成空格,默认一个tab转换成8个空格 """ """ S.expandtabs([tabsize]) -> string Return a copy of S where all tab ch...
Write a Python program to use regular expressions to determine the position of a substring and output a default message if absent. Go to: Python Data Type String Exercises Home ↩ Python Exercises Home ↩ Previous: Next:Write a Python program to wrap a given string into a paragraph of gi...