Question

Given a string sentence that consists of some words separated by a single space, and a string searchWord.

Write a function isPrefix to check if searchWord is a prefix of any word in sentence. A prefix of a string S is any leading contiguous substring of S. It returns the index of the word in sentence where searchWord is a prefix of this word (1-indexed).

If searchWord is a prefix of more than one word, return the index of the first word (minimum index). If there is no such word return -1.

Input: sentence = this problemo is an easy problemo, searchWord = pro

Output: 2

Explanation: pro is prefix of problemo which is the 2nd and the 6th word in the sentence, but we return 2 as it's the minimal index.

Answer 1

Solution:

#function to check weather the word in sentence has prefix as searchWord
def isPrefix(string,searchWord):
#converting the words in a given string in the form of list separated by spaces
lis=list(string.split(" "))
#iterating through all the elements of list
for i in lis:
#startswith( ) checks weather the element starts with searchWord
if i.startswith(searchWord):
#if the word starts with the searchWord then its index is returned
return lis.index(i)+1
#in case there is no word in list that starts with searchWord then return -1
return -1
#taking string as input from user
string=input("Enter the string :")
#taking searchWord as input from user
searchWord=input("Enter the prefix word to be searched :")
#calling function isPrefix to get the required result
print(isPrefix(string,searchWord))

Steps to solve :

• words in the string is converted in the form of list
• each word in list is now compared using startswith() with search word
• if the search is found then index of that word is returned
• incase there is no word in list that starts with search word then -1 is returned by function

Note: if you find any error in the above code it may be due to improper indentation ,so please provide proper indentation with the help of above image

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