How to loop over this 2D array and build sentences as per given column indexes?

[santosonit]

Hello!
I’ve tried getting help elsewhere, but no luck so far.
Given the 2D array of words below, how can I generate sentences, according to the indexes?

let ar = [
  ["Training", "für", "die", "Polizei"],
  ["Trainings", "", "das", "Polizisten"],
  ["Trainingseinheit", "", "", "Militär"]
];

const indexes = [0, 3, 2, 1];

let result = [];
for (let a = 0; a < ar.length; a++) {
  let sentence = [];
  indexes.forEach(function(index) {
    const col = ar.map(e => e[index]).flat();
    for (let c = 0; c < col.length; c++) {
      if (ar[c] == '') {
        c++
        continue;
      } else {
        sentence.push(ar[c]);
      }
    }
  })
  result.push(sentence)
}

This is the expected result:

let result = [
  ["Training für die Polizei"],
  ["Training für die Polizisten"],
  ["Training für die Militär"],
  ["Training für das Polizei"],
  ["Training für das Polizisten"],
  ["Training für das Militär"],
  ["Trainings für die Polizei"],
  ["Trainings für die Polizisten"],
  ["Trainings für die Militär"],
  ["Trainings für das Polizei"],
  ["Trainings für das Polizisten"],
  ["Trainings für das Militär"]...
]

I think it needs recursion, but being a beginner, it’s still hard for me. I would appreciate any help!

[JeremyLT]

I would not use recursion at all. You could, if you wanted to, but you would need to rework this into a function.

Can you better articulate what is supposed to happen with the blank strings?

[santosonit]

Hello @JeremyLT ! Thanks for your comment. For example, 2nd column only has one word, but that would be in all the sentences beginning with Training until sentences including all words in columns 3 and 4 are created.

[santosonit]

The function does give the result with 15 sentences, but the expected result is to contain 30, including, for example:
Training für das Polizei
Training für die Polizisten
Training für die Militär …:

let ar = [
  ['Training', 'für', 'die', 'Polizei'],
  ['Trainings', '', 'das', 'Polizisten'],
  ['Trainingseinheit', '', '', 'Militär'],
];

let result = [];

ar.forEach((el, index) => {
  let sentence = [el[0]];
  
  ar.forEach(el1 => {
    for(let i = 1; i < el1.length; i++) {
      if(el1[i]) {
        sentence[i] = el1[i]
      }
    }
    result.push(sentence.join(' '))
  })
});
console.log(result);

Here is a Fiddle, in case you feel like blessing it with your knowledge!

Much appreciated!

[hbar1st]

Please provide a more detailed explanation of the problem.