CODEWITHSUNDEEP
javascriptarraysecmascript-6
user3106579
user3106579

Reputation: 663

Remove first item of array of array

How do I remove 1 and 3 from below array in array?

[[1,2], [3,4,5]]

[[2],[4,5]]

was thinking about pop() but stuck somewhere.

Upvotes: 0

Views: 79

Answers (5)

Rohìt Jíndal
Rohìt Jíndal

Reputation: 27222

Try this :

var arr = [[1,2], [3,4,5]];

for (var innerArray of arr) {
  // Using array.splice()
  for (var element of innerArray) {
  	if (element === 1 || element === 3) innerArray.splice(innerArray.indexOf(element), 1);
  }
}

console.log(arr);

Upvotes: 0

Ori Drori
Ori Drori

Reputation: 192317

You can map the array, and got all items, but the the 1st, with Array.slice():

const arr = [[1,2], [3,4,5]];

const result = arr.map(item => item.slice(1));

console.log(result);

Upvotes: 0

Rise
Rise

Reputation: 1601

Try to use JavaScript built-in function shift().

var a = [[1,2], [3,4,5]];

a.map(item => { 
    item.shift();
    return item;
});

console.log(a); // [[2], [4, 5]]

Official guide: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/shift

Upvotes: 1

Justin Feakes
Justin Feakes

Reputation: 400

Loop through the main array as you normally would, like 

    let array = [[1,2], [3,4,5]]
    for (let el of array) {
         // Now you'll be accessing each array inside the main array,
         // YOu can now remove the first element using .shift()
         el.shift();
     }

Upvotes: 0

ZER0
ZER0

Reputation: 25322

You can use map and splice:

const a = [[1,2], [3,4,5]];

console.log(
  a.map(item => item.splice(1))
)

Basically you're mapping each item of the array with the same array without the first element (since splice mutate the array).

If you want have a copy also of the inner array, then you should use slice instead.

Upvotes: 0

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