Question 245834 in Javascript Question posted in
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Javascript – Put range of numbers in array as array of a single numbers

I want to put all numbers from min to max vars as a single number to array.
So in my example I want arr = [1,4,1,5,1,6] but i get [1,4, 1,5, ,1,6] as the result.
The problem is when i put separated values in array.
Would be very greatfull for any kind of help.

  let min = 14,
      max = 16,
      arr = [];

for (i=min; i<=max; i++) {
  arrPsh = i.toString().split("");
  arr.push(arrPsh);
}
for (i=0; i<arr.length; i++) {
  console.log(arr[i]);
}
Tags:

3

Answers


  1. 0

    Use spread syntax to pass each digit as a separate array element:

    https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

      let min = 14,
      max = 16,
      arr = [];

for (i=min; i<=max; i++) {
  arrPsh = i.toString().split("");
  arr.push(...arrPsh);
}
for (i=0; i<arr.length; i++) {
  document.write(arr[i] + "<br>");
}

    Actually you don’t need to split the string. The spread syntax gets the default iterator for a variable, accessed with str[Symbol.iterator](). In our case we have a string and its default iterator iterates characters in the string:

      let min = 14,
      max = 16,
      arr = [];

for (i=min; i<=max; i++) {
  arr.push(...i.toString());
}
for (i=0; i<arr.length; i++) {
  document.write(arr[i] + "<br>");
}

    Using Array::flat() would be definitely slower since it creates an intermediate array and introduces some unneeded magic of converting a wrong result to a proper one:

    Cycles: 10000 / Chrome/116
--------------------------------------------------------
Alexander    550/min  1.0x   557   561   576   589   550
jaabaa      1162/min  2.1x  1212  1162  1192  1866  1204
--------------------------------------------------------
https://github.com/silentmantra/benchmark

    <script benchmark="10000">

    let min = 1, max = 500;

// @benchmark Alexander
{
const arr = [];
for (let i=min; i<=max; i++) {
  arr.push(...i.toString());
}
arr;
}

// @benchmark jabaa
{
const arr = [];
for (i=min; i<=max; i++) {
  arrPsh = i.toString().split("");
  arr.push(arrPsh);
}
arr.flat();
}
</script>
<script src="https://cdn.jsdelivr.net/gh/silentmantra/benchmark/loader.js"></script>
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  2. 0

    You can flatten the array:

    let min = 14,
    max = 16,
    arr = [];

for (i=min; i<=max; i++) {
  arrPsh = i.toString().split("");
  arr.push(arrPsh);
}
arr = arr.flat();
for (i=0; i<arr.length; i++) {
  document.write(arr[i] + "<br>");
}
    Login or Signup to reply.
  3. 0

    Just join and split the array in the end:

    let min = 14,
    max = 16,
    arr = [];

for (let i=min; i<=max; i++)
    arr.push(i)

arr = arr.join('').split('')

console.log(arr)

    This will be 10x faster than other solutions.

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