获取 JavaScript 中字符串的所有子字符串

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.

Answer 1

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; }

Answer 2

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));

Answer 3

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);

Answer 4

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));

Answer 5

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+ = arr[k]
    }
    console.log(bag)
  }
}

Answer 6

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));
        }
    }
}

Answer 7

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;
}