Better way to modify values in a single array to different format

Question

This may be a duplicate question. But I didn't find any similar questions in this forum.

I'm trying to modify values in an array to different format.

arrayInput = ['A', 'B', 'C', 'D', 'E', 'F'];

arrayOutput= ['A;B', 'C;D', 'E;F'];

I got the solution with the following approach

let arrayInput = ['A', 'B', 'C', 'D', 'E', 'F']
arrayOutput = [arrayInput[0]+';'+ arrayInput[1], arrayInput[2]+';'+ arrayInput[3]];
if (arrayInput[4]) {
     let val = arrayInput[4] + (arrayInput[5] ? ';'+arrayInput[5] : '');
     arrayOutput.push(val);
}
console.log(arrayOutput);

But I am looking for a generic solution such that even if I have more items in array, it should generate the output in desired format.

['A', 'B', 'C', 'D', 'E', 'F', 'G'] ==> ['A;B', 'C;D', 'E;F', 'G']
['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'] ==> ['A;B', 'C;D', 'E;F', 'G;H']

Thanks for the support

PeterKA · Accepted Answer · 2022-05-12 16:25:45Z

2

You can use Array#reduce as in the following demo. Just in case there's an odd number of elements, I have included a test here ${arr[i+1] ? ";" + arr[i+1] : ""}; otherwise use ${arr[i+1]}, if you always have an even number of elements.

const arrayInput = ['A', 'B', 'C', 'D', 'E', 'F'],
      arrayOutput = arrayInput.reduce(
          (acc,cur,i,arr) => 
          i % 2 === 0 ? 
              [...acc,`${cur}${arr[i+1] ? ";" + arr[i+1] : ""}`] : 
              acc,
          []
      );

console.log( arrayOutput );
//OUTPUT: ['A;B', 'C;D', 'E;F'];

answered May 12, 2022 at 16:25

PeterKA

24.7k5 gold badges28 silver badges52 bronze badges

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

Comments

Omri Attiya · Accepted Answer · 2022-05-13 06:51:27Z

2

Use a for loop, and increment it by 2 every iteration:

const arrayInput = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];

const res = [];
for (let i = 0; i < arrayInput.length; i += 2) {
  const part1 = arrayInput[i];
  const part2 = arrayInput[i + 1];
  if (part1) {
    res.push(part1 + (part2 ? (';' + part2) : ''));
  }
}
console.log(res);

edited May 13, 2022 at 6:51

answered May 12, 2022 at 15:32

Omri Attiya

4,0473 gold badges22 silver badges38 bronze badges

2 Comments

Arun G Over a year ago

Thank you @Omri for the answer. but this solution is not working if odd number of elements present in array.

Omri Attiya Over a year ago

@ArunG you're right! edited my answer so it will work

Aneesh · Accepted Answer · 2022-05-12 15:34:33Z

1

You can try something like this (implementation based on array reduce and join):

const arrayInput = ['A', 'B', 'C', 'D', 'E', 'F'];

let temp = [];

const output = arrayInput.reduce((accumulator, item) => {
  if (temp.length < 2) {
    temp.push(item);
  } else {
    accumulator.push(temp.join(';'));
    temp = [];
  }
  return accumulator;
}, []);

console.log(output)

answered May 12, 2022 at 15:34

Aneesh

1,7256 silver badges14 bronze badges

Comments

Romylussone · Accepted Answer · 2022-05-12 15:38:00Z

1

Using a foreach :

let arrayInput = ['A', 'B', 'C', 'D', 'E', 'F','G','H','I']
let newArray = [];

arrayInput.forEach((e,i) => {
  if((i + 1)%2==0)
  {
    newArray[newArray.length -1] = `${newArray[newArray.length -1]};${e}`
  }
  else
  {    
    newArray.push((i + 1) < newArray.length ? `${e};` : e)
  }
});

console.log(newArray)

answered May 12, 2022 at 15:38

Romylussone

8331 gold badge9 silver badges21 bronze badges

Collectives™ on Stack Overflow

Better way to modify values in a single array to different format

4 Answers 4

Comments

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related