Extracting all words separated by non-alphabetical characters

Question

Given a string such as:

std::string word = "Hello World!it's@.-/sunday";

I want to extract all the words which are separated by non-alphabetical letters stored in a container like a vector, so for this case it would be:

Hello, World, it, s, sunday

My initial try was to use isalpha() along with an index count to substr() accordingly like so:

std::string word = "Hello World!it's@.-/sunday";
    int count = 0, index = 0; 
    std::string temp;  
    
     for (; count < word.length();count++){
        if (!isalpha(word[count])){
            temp = word.substr(index,count);
            index = count; 
        }
    }

But this does not work as I thought it would as the index does not update fast enough resulting in words mixed with non-alphabetical characters. Is there perhaps a function or a better way to extract said words?

score 1 · Accepted Answer · answered Oct 16 '20 at 14:20

1

You can try the following code. It constructs the words char by char.

#include <string>
#include <iostream>
#include <vector>
 
int main()
{
std::string phrase = "Hello World!it's@.-/sunday";
std::vector<std::string> words;  
std::string tmp;
 for (const char &c:phrase)
 {
        if (isalpha(c))
        {
            tmp.push_back(c);
        }
        else
        {
            words.push_back(tmp);
            tmp = "";
        }
 }
 if (!tmp.empty())
 {
     words.push_back(tmp);
 }
 
 for (const auto w : words)
 {
     std::cout << w << std::endl;
 }
 
 return 0;
}

answered Oct 16 '20 at 14:20

Jean-Marc Volle

3,113
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20

1

is there any built in function for that in C++? i often requred this. – pradeexsu Oct 16 '20 at 14:33
1

Yes you could use a regular expression to keep only alpha chars. See here for an example. https://regex101.com/r/3xHfeA/1 – Jean-Marc Volle Oct 16 '20 at 14:55

score 0 · Answer 2 · answered Oct 16 '20 at 17:02

0

one easy way is that replace all the non-alphabetical char to space than split around space.

answered Oct 16 '20 at 17:02

pradeexsu

1,029
1
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27

Extracting all words separated by non-alphabetical characters

2 Answers2