PHP - How to loop through a associative array and get the key name?

Question

My associative array:

$arr = array(
   1 => "Value1"
   2 => "Value2"
   10 => "Value10"
);

Using the following code, $v is filled with $arr's values

 foreach($arr as $v){
    echo($v);    // Value1, Value2, Value10
 }

How do I get $arr's keys instead?

 foreach(.....){
    echo($k);    // 1, 2, 10
 }

Answer 1

If you use array_keys(), PHP will give you an array filled with just the keys:

$keys = array_keys($arr);
foreach($keys as $key) {
    echo($key);
}

Alternatively, you can do this:

foreach($arr as $key => $value) {
    echo($key);
}

Answer 2

Have a look at this other post:

http://stackoverflow.com/questions/1219548/java-and-python-equivalent-of-phps-foreacharray-as-key-value

Answer 3

The following will allow you to get at both the key and value at the same time.

foreach ($arr as $key => $value)
{
  echo($key);
}

Answer 4

foreach($array as $k => $v)

Where $k is the key and $v is the value

Or if you just need the keys use array_keys()

Answer 5

You can do:

foreach (array_expression as $key => $value) {
 echo $key;
}

Answer 6

PHP array keys Documentation is here

Answer 7

 foreach($arr as $key=>$value){
    echo($key);    // key
 }

Answer 8

Oh I found it in the PHP manual.

foreach ($array as $key => $value){
    statement
}

The current element's key will be assigned to the variable $key on each loop.

Answer 9

Use $key => $val to get the keys:

<?php

$arr = array(
    1 => "Value1",
    2 => "Value2",
    10 => "Value10",
);

foreach ($arr as $key => $val) {
   print "$key\n";
}

?>