Is there a function like the php function key() in JavaScript/jQuery?

Question

I transferred a multidimensional array into JavaScript via <?php echo json_encode($my_array); ?> And I would like to compare entries of that JSON with other variables. So how could I get an object as string without the sub-entries?

Let's say my object is [Object { 1429={Object { 8766={...}, 8483={...}, 7345={...}}}}, Object { 9041={...}}]

So how could I get 1429 or 8766 as String? I know how to do that with a multidimensional array in PHP (there it is key()) - but what would it be in JavaScript?

In PHP the key() function simply returns the key of the array element that's currently being pointed to by the internal pointer. There is no internal pointer in the js object. What do you expect the key function to do? — Piotr Uchman
– Piotr Uchman, Commented Nov 26, 2013 at 16:13
JavaScript does not have the concept of "array pointer" (and I seldom use it in PHP). But I can't figure out what your object/array looks like (posting fake JSON doesn't help) and what rules make you choose between 1429 and 8766. Can you please post some real code? — Álvaro González
– Álvaro González, Commented Nov 26, 2013 at 16:15
If you want to get at the key while iterating through an object then yes that can be done with JS/jQuery. Post your loop and we can assist. — Shai
– Shai, Commented Nov 26, 2013 at 16:20

Piotr Uchman · Accepted Answer · 2013-11-26 16:17:19Z

1

In PHP the key() function simply returns the key of the array element that's currently being pointed to by the internal pointer.

for example (from manual):

<?php
 $array = array(
'fruit1' => 'apple',
'fruit2' => 'orange',
'fruit3' => 'grape',
'fruit4' => 'apple',
'fruit5' => 'apple');

// this cycle echoes all associative array
 // key where value equals "apple"
while ($fruit_name = current($array)) {
if ($fruit_name == 'apple') {
    echo key($array).'<br />';
}
next($array);
}
?>

There is no such thing in the js like internal pointer in object, so there is no similar function.

answered Nov 26, 2013 at 16:17

Piotr Uchman

5703 silver badges14 bronze badges

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

1 Comment

user2718671 Over a year ago

Ah ok! Thank you! Then I'll have to find another solution.

Venkata Krishna · Accepted Answer · 2013-11-26 16:25:07Z

1

Just an example of what I think you want. You can extend on this more.

var obj = {
    "5": "some",
    "8": "thing"
};
var keys = $.map(obj, function (value, key) {
    return key;
});
//result keys: ["5", "8"]

JSFIDDLE DEMO - open the console to see the result.

answered Nov 26, 2013 at 16:25

Venkata Krishna

15.2k5 gold badges45 silver badges57 bronze badges

1 Comment

user2718671 Over a year ago

Thank you! My json is not well formatted - so in my case it returns just [0, 1] because i need it for the highest level in my array, not the lowest.

Collectives™ on Stack Overflow

Is there a function like the php function key() in JavaScript/jQuery?

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related