how to map an array with uppercase function in javascript?

Question

I'm interested if there is any function like array_map or array_walk from php.

Don't need an for that travels all the array. I can do that for myself.

var array = ['dom', 'lun', 'mar', 'mer', 'gio', 'ven', 'sab'];
// i would like something like this if exists - function(array, 'upperCase');

Frédéric Hamidi · Accepted Answer · 2013-02-26T10:03:48.563

You can use $.map() in order to apply String.toUpperCase() (or String.toLocaleUpperCase(), if appropriate) to your array items:

var upperCasedArray = $.map(array, String.toUpperCase);

Note that $.map() builds a new array. If you want to modify your existing array in-place, you can use $.each() with an anonymous function:

$.each(array, function(index, item) {
    array[index] = item.toUpperCase();
});

Update: As afanasy rightfully points out in the comments below, mapping String.toUpperCase directly will only work in Gecko-based browsers.

To support the other browsers, you can provide your own function:

var upperCasedArray = $.map(array, function(item, index) {
    return item.toUpperCase();
});

@afanasy, true, I'm probably using Firefox too much. I updated my answer with a portable mapping solution. — Frédéric Hamidi, Feb 26 '13 at 10:04

score 11 · Answer 2 · answered Apr 20 '12 at 02:24

Check out JavaScript Array.map for info on the official JavaScript map function. You can play around with the sample there to see how the function works. Try copying this into the example box:

var array = ['dom', 'lun', 'mar', 'mer', 'gio', 'ven', 'sab'];
var uppers = array.map(function(x) { return x.toUpperCase(); });
console.log(uppers);

And it will print:

DOM,LUN,MAR,MER,GIO,VEN,SAB

score 8 · Answer 3 · answered Oct 30 '14 at 11:10

8

This may be an overkill but you can also do

var upperCaseArray = array.map(String.prototype.toUpperCase.call.bind(String.prototype.toUpperCase));

answered Oct 30 '14 at 11:10

Sharat M R

335
3
8

@nkron's answer is similar to this, but less verbose. – Ceasar Dec 09 '15 at 19:05
2

That code is a bit confusing because the `String.prototype.toUpperCase.call` part of the code is just accessing the [Function's call](http://www.javascripture.com/Function#call) method. That method is the same for all Functions so you can stick any Function to the left of .call without changing the behavior. I'd suggest changing it to `Function.prototype.call...` to be explicit that you are using Function's call, not a special feature of the toUpperCase function. – nkron Apr 13 '16 at 20:49
The clearer example is: `['a','b','c'].map(Function.prototype.call.bind(String.prototype.toUpperCase))` – Ivan Hamilton May 04 '16 at 01:50

Endless · Answer 4 · 2019-05-29T09:12:37.877

And here is the one-liner without creating a loop or a function that is ES3 compatible It's alos faster since you only call toUpperCase once

// watch out for strings with comma (eg: ["hi, max"]) then use custom join/split()
// or just use something safer such as Array.map()
var uppercaseArray = array.toString().toUpperCase().split(",");
var uppercaseArray = array.join(0).toUpperCase().split(0);
var uppercaseArray = (array+"").toUpperCase().split(",");

score 5 · Answer 5 · answered Mar 30 '12 at 08:59

You can implement a function for it:

Array.prototype.myUcase=function()
{
  for (i=0;i<this.length;i++)
    {
    this[i]=this[i].toUpperCase();
    }
}

USAGE

var fruits=["Banana","Orange","Apple","Mango"];
fruits.myUcase();

RESULT

BANANA,ORANGE,APPLE,MANGO

Reference LINK

stusmith · Answer 6 · 2012-03-30T09:11:45.413

4

You could consider using the Underscore.js library which provides standard functional operations.

Then the code would be as simple as:

_.map(array, function (x) { return x.toUpperCase(); });

edited Mar 30 '12 at 09:11

answered Mar 30 '12 at 08:57

stusmith

14,003
7
56
89

1

also: `_.map(array, _.upperCase)` – guy mograbi Mar 08 '18 at 22:41

score 3 · Answer 7 · answered Mar 30 '12 at 08:59

3

map() is somehow similar to array_walk

http://jqapi.com/#p=map

answered Mar 30 '12 at 08:59

mamoo

8,156
2
28
38

score 2 · Answer 8 · answered Mar 30 '12 at 08:57

2

Javascript has a map() method. A good reference is at http://www.tutorialspoint.com/javascript/array_map.htm

answered Mar 30 '12 at 08:57

Chetter Hummin

6,687
8
32
44

score 1 · Answer 9 · answered Apr 05 '16 at 00:43

1

I understand it is a little late to the party, but I wanted to add this here as another Delegation way of doing it.

var array = ['dom', 'lun', 'mar', 'mer', 'gio', 'ven', 'sab'];

"".toUpperCase.apply(array).split(',')

answered Apr 05 '16 at 00:43

james emanon

11,185
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wow.... care to explain how it's working. how/why is apply converting array to string – aWebDeveloper Jun 09 '16 at 10:12
sure. Since I wanted to 'toUpperCase', I needed to be able to delegate to it, or borrow that functionality. Since, I needed an array to do it, I had to somehow pass the "context" IN to the "toUpperCase". apply (since we are using an array), allows this. because I didn't pass a second arg, the first arg "array", is the context. So basically, it spreads it out for me... then I split it to turn it back into an array. – james emanon Jun 09 '16 at 23:09

score 0 · Answer 10 · answered Apr 07 '17 at 04:35

Similar to a previous for loop answer, this one uses some of the more basic features of javascript:

function looptoUpper(arr){
    var newArr = [];
    for (var i = 0; i < arr.length; i++){
        newArr.push(arr[i].toUpperCase());
    }
    return newArr;
}
looptoUpper(['dom', 'lun', 'mar', 'mer', 'gio', 'ven', 'sab']);

how to map an array with uppercase function in javascript?

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