How to get all the keys of an associative array in PHP

Use the PHP array_keys() function

You can use the PHP array_keys() function to get all the keys out of an associative array.

Let's try out an example to understand how this function works:

<?php
$cities = array("France"=>"Paris", "India"=>"Mumbai", "UK"=>"London", "USA"=>"New York");
// Get keys from cities array
print_r(array_keys($cities));
?>

You can also use the PHP foreach loop to find or display all the keys, like this:

<?php
$cities = array("France"=>"Paris", "India"=>"Mumbai", "UK"=>"London", "USA"=>"New York");
// Loop through cities array
foreach($cities as $key => $value){
    echo $key . " : " . $value . "<br>";
}
?>