How doI reduce an array to a specific amount in javascript/jquery/undescore?

Question

I have an array like:

["a", "b", "c", "d", "e"]

Now I want to just have the first 3 items. How would I remove the last two dynamically so that I could also have a 20 letter array, but reduce that down to the first 3 as well.

Please refer to similar question stackoverflow.com/questions/3954438/… — adamb
– adamb, Commented Nov 1, 2012 at 16:03
What if you construct another array with the first three elements and than exclude that original array, if you don't need it anymore? — rafaelbiten
– rafaelbiten, Commented Nov 1, 2012 at 16:03

Kyle · Accepted Answer · 2012-11-01 16:05:41Z

5

var a = ["a", "b", "c", "d", "e"];
a.slice(0, 3); // ["a", "b", "c"]

var b = ["a", "b", "c", "d", "e", "f", "g", "h", "i"];
b.slice(0, 3); // ["a", "b", "c"]

answered Nov 1, 2012 at 16:05

Kyle

22.3k2 gold badges63 silver badges63 bronze badges

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

Comments

rjz · Accepted Answer · 2012-11-01 16:05:58Z

3

How about Array.slice?

var firstThree = myArray.slice(0, 3);

answered Nov 1, 2012 at 16:05

rjz

16.5k3 gold badges39 silver badges35 bronze badges

Comments

Joe Enos · Accepted Answer · 2012-11-01 16:05:46Z

2

The splice function seems to be what you're after. You could do something like:

myArray.splice(3);

This will remove all items after the third one.

answered Nov 1, 2012 at 16:05

Joe Enos

40.6k11 gold badges86 silver badges144 bronze badges

Comments

Bergi · Accepted Answer · 2012-11-01 16:06:56Z

2

To extract the first three values, use slice:

var my_arr = ["a", "b", "c", "d", "e"];
var new_arr = my_arr.slice(0, 3); // ["a", "b", "c"]

To remove the last values, use splice:

var removed = my_arr.splice(3, my_arr.length-3); // second parameter not required
// my_arr == ["a", "b", "c"]

answered Nov 1, 2012 at 16:06

Bergi

671k162 gold badges1k silver badges1.5k bronze badges

Comments

Dinesh P.R. · Accepted Answer · 2012-11-02 11:14:31Z

0

In underscore.js we can use the first function

_.first(array, [n]) Alias: head

Returns the first element of an array. Passing n will return the first n elements of the array.

_.first(["a", "b", "c", "d", "e"],3);
=> ["a", "b", "c"]

answered Nov 2, 2012 at 11:14

Dinesh P.R.

7,4467 gold badges39 silver badges45 bronze badges

Collectives™ on Stack Overflow

How doI reduce an array to a specific amount in javascript/jquery/undescore?

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related