how to generate random strings twice

Question

function generate() {
  const notations = [" U", " D", " R", " L", " F", " B"];

  const switches= ["", "\'", "2"]; 

  let array = [];

  let last = '';

  let random = 0;

  for (let i = 0; i < 20; i++) {
      
      do {
         random = Math.floor(Math.random() * notations.length);
      } while (last == notations[random]) 


  last = notations[random];

  let Item = notations[random] + switches[parseInt(Math.random()*switches.length)];

  array.push(Item);
  }

  let scrambles = "";

  for(i=0; i< 20; i++) {
     scrambles += array[i];
  }

document.getElementById("div").innerHTML = scrambles;
}

so i have function that generates random string so output will be something like R U' B2 R2 L F L2 B U2 B U F' L' B2 R' L D2 U' L2 R

and i want to generate the random letters twice so output will be something like

R U' B2 R2 L F L2 B U2 B U F' L' B2 R' L D2 U' L2 R
B R' U' F' D L U2 F' R' B D U F R' L' F U2 D L R

i found a solution which is by duplicating the codes like this

function generate() {
  const notations = [" U", " D", " R", " L", " F", " B"];

  const switches= ["", "\'", "2"]; 

  let array = [];

  let last = '';

  let random = 0;

  for (let i = 0; i < 20; i++) {
      
      do {
         random = Math.floor(Math.random() * notations.length);
      } while (last == notations[random]) 


  last = notations[random];

  let Item = notations[random] + switches[parseInt(Math.random()*switches.length)];

  array.push(Item);
  }

  let scrambles = "";

  for(i=0; i< 20; i++) {
     scrambles += array[i];
  }

 const notations2 = new Array(" U", " D", " R", " L", " F", " B");

  const switches2= ["", "\'", "2"]; 

  let array2 = [];

  const last2 = '';

  const random2 = 0;

  for (let i = 0; i < 20; i++) {
      
      do {
         random2 = Math.floor(Math.random() * notations2.length);
      } while (last == notations2[random2]) 


  last2 = notations2[random2];

  let Item2 = notations2[random2] + switches2[parseInt(Math.random()*switches2.length)];

  array.push(Item2);
  }

  let scrambles2 = "";

  for(i=0; i< 20; i++) {
     scrambles2 += array[i];
  }
document.getElementById("div").innerHTML = scrambles + "<br>" + scrambles2;
}

but its not efficient, is there a faster way and more efficient way to do this?

You have "const random = 0;" and later on you apply new value to random. You can't, it's const. (Same with "last") — Dalibor
– Dalibor, Commented Apr 21, 2021 at 11:49
why not simply change the for loop to have the condition be i < 40 instead of i < 20 — TUTAMKHAMON
– TUTAMKHAMON, Commented Apr 21, 2021 at 11:54
@TUTAMKHAMON ah its because i want to add a line break, i have edited the post. um is it possible to do it with i < 40? — I_love_vegetables
– I_love_vegetables, Commented Apr 21, 2021 at 11:58
Have the function return the generated string. Then you can call it as many times as you want and append the result wherever you want. — Heretic Monkey
– Heretic Monkey, Commented Apr 21, 2021 at 12:01

TUTAMKHAMON · Accepted Answer · 2021-04-21 12:46:44Z

1

Just have the generate function return the scrambles and call it twice:

function generate(n) {
  const notations = [" U", " D", " R", " L", " F", " B"];
  const switches = ["", "\'", "2"];

  let last = null;
  let scrambles = "";

  for (let i = 0; i < n; ++i) {
    //subtract 1 when you can't select the same as the last
    let available_notations = notations.length - (last === null ? 0 : 1);

    //one random for all combinations
    let random = Math.floor(Math.random() * available_notations * switches.length);

    let nt = Math.floor(random / switches.length); //notation value
    let sw = Math.floor(random % switches.length); //switch value

    if (last !== null && last <= nt) nt += 1; //add 1 when value bigger than last
    last = nt;

    scrambles += notations[nt] + switches[sw];
  }
  return scrambles;
}

document.getElementById("div").innerHTML = generate(20) + '<br/>' + generate(20);

<div id="div"></div>

edited Apr 21, 2021 at 12:46

answered Apr 21, 2021 at 12:05

TUTAMKHAMON

6204 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

I_love_vegetables Over a year ago

hi thanks for answering, im wondering if there is a way to only have one div element in the html and append the <br> and the paragraph in JS

TUTAMKHAMON Over a year ago

Yes, edited the answer to reflect that. Also made the generation of random notations more efficient.

thabs · Accepted Answer · 2021-04-21 12:08:43Z

1

You have already wrapped your code in a function, so just call it twice (or as many times as you want).

As others have already suggested, simply return your scrambles string from generate() and then you can do something like:

function generateNTimes(n) {
    const scrambles = [];
    for (let i = 0; i < n; i++) {
        scrambles.push(generate());
    }
    document.getElementById("div").innerHTML = scrambles.join('<br>');
}

answered Apr 21, 2021 at 12:08

thabs

6433 silver badges16 bronze badges

Collectives™ on Stack Overflow

how to generate random strings twice

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related