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javascript [1,2,3,4] becomes 12, 23, 34

Time:11-12

i like to ask for advise how to let this array [1,2,3,4] to become 12, 23, 34?

this initial is a number 1234, i split them

let sum
sum = String(this.numbers).split("").map(Number);
console.log('numbers set1', sum)
<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

so from here it becomes [1,2,3,4]

how can i join/combine/concat then to become 12, 23, 34 respectively?

thank you very much for Hello World's guidance

thank you

CodePudding user response:

You may want to write simple algorithm to get pairs of those numbers. Try to traverse the string/list and insert the new values into another list.

Sudo code can be something like: let's say you have arr with numbers [1,2,3,4]

for i = 1 to N:
 string sum = arr[i-1] arr[i];
 list.push(sum)

CodePudding user response:

You can easily achieve the result using split, map, and filter

const num = 1234;
const result = String(num)
  .split("")
  .map((n, i, src) => (src.length !== i   1 ? `${n}${src[i   1]}` : null))
  .filter(Boolean)
  .map(Number);

console.log(result);
<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

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