How do I pass multiple arrays to my function in a specific format?

Question

I've been working on permutations within javascript so that I can colelct numbers that corrospond to letters for example a telephone keypad. What I want to do is take those letters that corrospond to keys, split them into an arrays and pass those arrays to a function to find all possible permutations or combinations.

Let's look at what I have so far. I have the numbers and their letters stored as an array

var array = [{ key: '2', value: 'a,b,c'}, 
             { key: '3', value: 'd,e,f'},
             { key: '4', value: 'g,h,i'}]

I then want to iterate over this array and grab the letters that corrospond to the keys.

for(var thingy of array){
    var letters = thingy.value;
    var splitArray = letters.split(',')
}

That gives me the letters split up as ["a", "b", "c"] so now I want take these multiple arrays and pass them to a function that looks for all combinations. This is a function I got from this thread: Finding All Combinations of JavaScript array values

function allPossibleCases(arr) {
      if (arr.length === 0) {
            return [];
          } 
        else if (arr.length ===1){
        return arr[0];
        }
        else {
            var result = [];
            var allCasesOfRest = allPossibleCases(arr.slice(1));
                for (var c in allCasesOfRest) {
                    console.log("huh?" + allCasesOfRest);
                  for (var i = 0; i < arr[0].length; i++) {
                    result.push(arr[0][i] + allCasesOfRest[c]);
                  }
                }
                return result;
              }
            }

This function expects the format of the arrays to be something like

var allArrays = [['a', 'b'], ['c', 'z'], ['d', 'e', 'f']];

So my question is how do I pass my newly split arrays to this function in the correct format and also at what point should I do it? Should I carry this out in the iteration loop of the arrays?

Here is my complete code so far that I've yet to get working.

 $(function() {                                        


        var array = [{ key: '2', value: 'a,b,c'}, 
                     { key: '3', value: 'd,e,f'},
                     { key: '4', value: 'g,h,i'}]

        array.toString();
        console.log(array);

        //Iterate over the array and find the value label            
        for(var thingy of array){
            var letters = thingy.value;
            //Split the characters up
            var splitarray = letters.split(',')
            //Output all arrays via function to find permutations
            //Hmm should this live here?
           console.log(allPossibleCases(splitarray));             
        }                
    });



function allPossibleCases(arr) {
      if (arr.length === 0) {
        return [];
      } 
    else if (arr.length ===1){
    return arr[0];
    }
    else {
        var result = [];
        var allCasesOfRest = allPossibleCases(arr.slice(1));  // recur with the rest of array
        for (var c in allCasesOfRest) {
            console.log("huh?" + allCasesOfRest);
          for (var i = 0; i < arr[0].length; i++) {
            result.push(arr[0][i] + allCasesOfRest[c]);
          }
        }
        return result;
      }
    }

and which numbers do you need to get a permutation from? or better what input do you need? — Nina Scholz, May 12 '17 at 09:11
why the `[['a', 'b'], ['c', 'z'], ['d', 'e', 'f']]` array have three elements while others have two? — brk, May 12 '17 at 09:15
@brk That was just an example based on the thread I got the function from. That is an example showing that the function needs mutiple arrays. I have mutliple arrays but I need to pass them to the function. — Yanayaya, May 12 '17 at 09:22
@NinaScholz It's like a phone so if someone enters 2 the letters could be a,b,c and I'd like to get the permutations of that. — Yanayaya, May 12 '17 at 09:28

score 1 · Accepted Answer · answered May 12 '17 at 09:28

You could map the array, you have with the splitted values and use it as argument for allPossibleCases.

result = allPossibleCases(array.map(a => a.value.split(',')));

function allPossibleCases(arr) {
    if (arr.length === 0) {
        return [];
    } 
    if (arr.length === 1) {
        return arr[0];
    }
    var result = [];
    var allCasesOfRest = allPossibleCases(arr.slice(1)); // recur with the rest of array
    for (var c in allCasesOfRest) {
        // console.log("huh?" + allCasesOfRest);
        for (var i = 0; i < arr[0].length; i++) {
            result.push(arr[0][i] + allCasesOfRest[c]);
        }
    }
    return result;
}

var array = [{ key: '2', value: 'a,b,c' }, { key: '3', value: 'd,e,f' }, { key: '4', value: 'g,h,i' }],
    result = allPossibleCases(array.map(a => a.value.split(',')));
    
console.log(result);

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

This answer works, it's better and I can remove the secondary split and iteration. Makes sense. Thanks @NinaScholz — Yanayaya, May 12 '17 at 09:45

How do I pass multiple arrays to my function in a specific format?

1 Answers1