Get all substrings of a string in JavaScript

Question

I have the following function to get all of the substrings from a string in JavaScript. I know it's not correct but I feel like I am going about it the right way. Any advice would be great.

 var theString     = 'somerandomword',
     allSubstrings = []; 

getAllSubstrings(theString);

function getAllSubstrings(str) {

  var start = 1;

  for ( var i = 0; i < str.length; i++  ) {

     allSubstrings.push( str.substring(start,i) ); 

  }

} 

console.log(allSubstrings)

Edit: Apologies if my question is unclear. By substring I mean all combinations of letters from the string (do not have to be actual words) So if the string was 'abc' you could have [a, ab, abc, b, ba, bac etc...] Thank you for all the responses.

This should be useful http://stackoverflow.com/questions/4547609/how-do-you-get-a-string-to-a-character-array-in-javascript — Omid Farvid, Nov 26 '16 at 13:28
It is unclear what you mean with 'substrings'. If you're trying to get each word as its own value you would have to split the string specifically at A, B, C. But what if the word is not 'somerandomword'? They you would either have to use a dictionary or another array of words you would like your function to split by. Each of these words cannot be defined as a 'word'. — Tommie, Nov 26 '16 at 13:55
What would be a better way to phrase this question and i'll update it. — user2085143, Nov 26 '16 at 16:51
Your new edit does clarify things. I'm curious though -- why would you would want to do this? :) — Tommie, Nov 26 '16 at 19:54

score 34 · Accepted Answer · answered Nov 26 '16 at 13:29

34

You need two nested loop for the sub strings.

function getAllSubstrings(str) {
  var i, j, result = [];

  for (i = 0; i < str.length; i++) {
      for (j = i + 1; j < str.length + 1; j++) {
          result.push(str.slice(i, j));
      }
  }
  return result;
}

var theString = 'somerandomword';
console.log(getAllSubstrings(theString));

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Nov 26 '16 at 13:29

Nina Scholz

376,160
25
347
392

5

this solution gives only parts of the string, but does no make permutations of it. – Nina Scholz Nov 26 '16 at 15:51
1

This doesn't produce every substring possible like "os". It only moves to the right. – Badmaash Oct 18 '21 at 12:10
@Badmaash, do you wnat a permutation of all characters instead? – Nina Scholz Oct 18 '21 at 15:14
Not me but I think that's exactly what questioner is looking for. Look at his Edit :) – Badmaash Oct 19 '21 at 11:05
@Badmash Left to right only – Adam Ziolkowski Nov 05 '21 at 19:34

score 3 · Answer 2 · edited Jun 30 '20 at 00:54

A modified version of Accepted Answer. In order to give the minimum string length for permutation

function getAllSubstrings(str, size) {
  var i, j, result = [];
  size = (size || 0);
  for (i = 0; i < str.length; i++) {
    for (j = str.length; j - i >= size; j--) {
      result.push(str.slice(i, j));
    }
  }
  return result;
}

var theString = 'somerandomword';
console.log(getAllSubstrings(theString, 6));

score 2 · Answer 3 · edited Jun 30 '20 at 00:52

2

Below is a recursive solution to the problem

let result = [];

function subsetsOfString(str, curr = '', index = 0) {
  if (index == str.length) {
    result.push(curr);
    return result;
  }
  subsetsOfString(str, curr, index + 1);
  subsetsOfString(str, curr + str[index], index + 1);
}

subsetsOfString("somerandomword");
console.log(result);

edited Jun 30 '20 at 00:52

codejockie

9,020
4
40
46

answered Feb 07 '20 at 15:10

Paras Wadhwa

64
6

score 0 · Answer 4 · answered Dec 10 '21 at 23:14

An answer with the use of substring function.

function getAllSubstrings(str) {
  var res = [];
  for (let i = 0; i < str.length; i++) {
    for (let j = i + 1; j <= str.length; j++) {
      res.push(str.substring(i, j));
    }
  }
  return res;
}
var word = "randomword";
console.log(getAllSubstrings(word));

Manoranjan Sethi · Answer 5 · 2022-12-17T06:33:57.713

0

Below is a simple approach to find all substrings


    var arr = "abcde";

     for(let i=0; i < arr.length; i++){

      for(let j=i; j < arr.length; j++){

      let bag ="";
      for(let k=i; k<j; k++){
       bag = bag + arr[k]
    }
    console.log(bag)
  }
}

edited Dec 17 '22 at 06:33

answered Jan 12 '22 at 12:50

Manoranjan Sethi

1
1

score 0 · Answer 6 · edited May 20 '22 at 06:02

0

function generateALlSubstrings(N,str){
    
    for(let i=0; i<N; i++){

        for(let j=i+1; j<=N; j++){

            console.log(str.substring(i, j));
        }
    }
}

edited May 20 '22 at 06:02

Suraj Rao

29,388
11
94
103

answered May 20 '22 at 06:00

vrushabh veer

1

1

Strings inherently have a length property. having to input `N` seems unnecessary. – General Grievance May 20 '22 at 14:20

score -1 · Answer 7 · answered May 04 '20 at 01:33

function getSubstrings(s){
    //if string passed is null or undefined or empty string
    if(!s)   return []; 

    let substrings = [];

    for(let length = 1 ; length <= s.length; length++){
        for(let  i = 0 ; (i + length) <= s.length ; i++){
            substrings.push(s.substr(i, length));
        }
    }

    return substrings;
}

Get all substrings of a string in JavaScript

7 Answers7

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