CODEWITHSUNDEEP
javascript
kittu
kittu

Reputation: 7018

push duplicate values into array based on length provided

I want to insert duplicate values into array based on length provided like this:

var a = ['bar', 'google', 'mod'];
var b = [];

var dataLength = 4;

output should look like: var a = ['bar', 'bar','bar','bar', 'google', 'google', 'google', 'google', 'mod', 'mod','mod', 'mod'];

I tried this:

var dataLength = 4;
var a = ['bar', 'google', 'mod'];
var b = new Array(dataLength);
var c = [];

for (let i = 0; i < a.length; i++) {
    c.push((b.fill(a[i]).toString()))
}

It works but not sure this is a good way to do this.

Upvotes: 0

Views: 150

Answers (6)

Scott Sauyet
Scott Sauyet

Reputation: 50797

A fairly simple technique is just to use flatMap with Array.prototype.fill:

const repeatN = (n, arr) => arr .flatMap (a => Array (n) .fill (a) )

console .log (
  repeatN( 4,  ['barclays', 'google', 'vod'] )
)

If your environment doesn't support flatMap, it's not hard to shim, or you could use this instead:

const repeatN = (n, arr) => 
  arr.map(a => Array (n) .fill (a)) .reduce ( (a, b) => a .concat (b) )

Upvotes: 1

Shilly
Shilly

Reputation: 8589

Two of our newest Array methods, flatMap() and fill() are perfect for this:

.flatMap() will do a mapping and merge the returned arrays into one array. .from() can create a new array for a specific length. .fill() fills an array with a certain value.

So all 3 combined we get this little oneliner:

var a = ['barclays', 'google', 'vod'];
var length = 4;
var b = a.flatMap( word => Array.from({ length }).fill( word ));

console.log( b );

Upvotes: 1

Ghoul Ahmed
Ghoul Ahmed

Reputation: 4826

Try this:

const a = ["barclays", "google", "vod"];

const result = (num) => a.reduce((acc, ele) => acc.concat(Array(num).fill(ele)), []);

console.log(result(10))

Upvotes: 2

Kevin.a
Kevin.a

Reputation: 4296

var a = ['barclays', 'google', 'vod'];
var b = [];

var dataLength = 4;

for (let i = 0; i < dataLength; i++) {
   for (let o = 0; o < a.length; o++){
       b.push(a[o]);
   }
}

console.log(b);

Something like this,except in my example its not sorted.

Upvotes: 0

Jaydeep
Jaydeep

Reputation: 1716

Add nested for loop, loop through your data length and push the element in your array.

var a = ['barclays', 'google', 'vod'];
var b = [];

var dataLength = 4;

for (let i = 0; i < a.length; i++) {
   for(let j=0;j<dataLength;j++) {
     b.push(a[i])
   }
}

Upvotes: 1

Wimanicesir
Wimanicesir

Reputation: 5122

var a = ['barclays', 'google', 'vod'];
var b = [];

var dataLength = 4;
// Loop every element of a
for (let i = 0; i < a.length; i++) {
  // Loop 4 times and push current element
  for (let j = 0; j < dataLength; j++) {
    b.push(a[i])
  }
}

console.log(b)

Upvotes: 2

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