PHP add to beginning of array without reordering

Question

I've tried searching for an answer to my question but I couldn't find one that did it without reordering numerical indexes.

Is there a way to add a string to the beginning of an array without reordering the keys (numerical keys) without using a loop?

Thanks

EDIT:

I'll try to explain the scenario. (I'm using CodeIgniter).

I have an array that is used throughout my app. This array is also used to create a dropdown and to validate these dropdown values in a form that I have. What I'd like to do is insert a blank value to the beginning of the array so that my dropdown has a blank option select by default.

So from this

1 => Hello
2 => World

to

'' => ''
1 => Hello
2 => World

I'm not sure what you're getting at. Any example input/output? — BoltClock
– BoltClock, Commented Mar 12, 2011 at 17:13
What index should the new element have? Why do you need this condition (no reordering of the keys)? If you access the elements by key anyway, then the order does not matter. And if you iterate over them, then the index does not matter. So why do you need it? Maybe there is a better strategy for your case. — Felix Kling
– Felix Kling, Commented Mar 12, 2011 at 17:16
@BoltClock @Felix-Kling @yoda - I've tried to explain a bit in my original post - Thanks — RS7
– RS7, Commented Mar 12, 2011 at 17:32

edorian · Accepted Answer · 2011-03-12 17:49:50Z

9

Since you don't want to change the numerical indexes i assume array_unshift will not work.

So maybe if you know the indexes you could do it like that:

$x = array(1 => 1, 2 => 2, 3 => 3); 
$y = array(1101 => 123);
var_dump( $y + $x );

/* Output:
array(4) {
  [1101]=>
  int(123)
  [1]=>
  int(1)
  [2]=>
  int(2)
  [3]=>
  int(3)
}
*/

Note that the key is now really in front of the array so foreach will work fine.

Response to edit:

$x = array(1 => "Hello", 2 => "Welt"); 
$y = array("" => "");

var_dump($y + $x);

/*
array(3) {
  [""]=>
  string(0) ""
  [1]=>
  string(5) "Hello"
  [2]=>
  string(4) "Welt"
}
*/

edited Mar 12, 2011 at 17:49

answered Mar 12, 2011 at 17:17

edorian

39k15 gold badges129 silver badges145 bronze badges

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

1 Comment

hadees Over a year ago

The problem with this method is if you have conflicting keys they will get overwritten.

Collectives™ on Stack Overflow

PHP add to beginning of array without reordering

1 Answer 1

Response to edit:

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Response to edit:

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related