making combination of words in javascript

Question

Can someone tell me me how to make word combinations in javascript. I am new to programming. I did this

var words=["word1","word2","word3","word4"];

Ex:

words: [
    "word1",
    "word2",
    "word3",
    "word4"
]

output:

"word1 word2",
"word1 word3",
"word2 word3",
"word1 word2 word3",
"word2 word3 word4",
"word1 word3 word4"

i started with a loop. concatenating each with others. but ended up with duplicates like "word1 word2" , "word2 word1" — user3501538, Dec 01 '15 at 18:54
show what you have done, and then we can see how best to help — depperm, Dec 01 '15 at 18:55
Your output seems random, do you mean you want all combinations of items in the array printed? if so you are missing multiple combinations — abc123, Dec 01 '15 at 19:04
i dont want duplictaes. like "word1 word2" and "word2 word1" are same — user3501538, Dec 01 '15 at 19:06
http://stackoverflow.com/questions/127704/algorithm-to-return-all-combinations-of-k-elements-from-n you are also missing `word1 word2 word3 word4` — abc123, Dec 01 '15 at 19:10
i need on 2 & 3 combination as i said in question. so no need of word1 word2 word3 word4 — user3501538, Dec 01 '15 at 19:12
I do not understand your question, post the full desired output that you expect. — ElChiniNet, Dec 01 '15 at 19:22

undefined · Accepted Answer · 2015-12-01T19:31:56.963

This is one of way of doing it:

var ret = ["word1","word2","word3","word4"].reduce(function(ret, el, i, arr) {
     var n = arr.slice(++i);
     ret = ret.concat(n.map(function(_el) {
       return el + ' ' + _el;
     }));
     return ret;
}, []);

update: If I have understood the (updated) question properly the following snippet should do the trick:

var ret = ["word1", "word2", "word3", "word4", "word5"].reduce(function (ret, el, i, arr) {
  var n = arr.slice(++i);
  [2, 3].forEach(function (c) {
    ret = ret.concat(n.map(function (_, i) {
      return [el].concat(n.slice(i)).slice(0, c).join(' ');
    }));
  });
  if ( i === arr.length - 1 ) ret.pop();
  return ret;
}, []);

abc123 · Answer 2 · 2015-12-01T19:49:14.287

Plunkr

JS

// array of words
var words = ["word1", "word2", "word3", "word4"];
// array to hold results
var result = [];
// number of times we need to iterate to check over all possible combinations
var setCount = Math.pow(2, words.length) - 1;
// loop over iterations
for (var i = 0; i < setCount; i++) {
  // array to hold this result
  var innerList = [];

  for (var j = 0; j < words.length; j++) {
    // Each position in the initial list maps to a bit here
    var position = 1 << j;
    // if the bits when bitwise AND are position then this is unique match
    if ((i & position) == position) {
      // insert into inner list
      innerList.push(words[j]);
    }
  }
  // insert into results if it isn't empty or a size of 1
  if(innerList.length !== 0 && innerList.length !== 1) {
    result.push(innerList);
  }
}

// purely for printing
for (var i = 0; i < result.length; i++) {
  console.log(result[i]);
}
console.log(result.length);

Taken from: http://blogs.msmvps.com/kathleen/2013/12/31/algorithm-find-all-unique-combinations-in-a-list/

Output

["word1", "word2"] ["word1", "word3"] ["word2", "word3"] ["word1", "word2", "word3"] ["word1", "word4"] ["word2", "word4"] ["word1", "word2", "word4"] ["word3", "word4"] ["word1", "word3", "word4"] ["word2", "word3", "word4"]

The user wants 2-3 combinations only. The script needs a little modification. — ElChiniNet, Dec 01 '15 at 19:24

making combination of words in javascript

2 Answers2

Plunkr

Output