Array Functions

PHP array_key_first() Function

Topic: PHP Array ReferencePrev|Next


The array_key_first() function gets the first key of an array.

The following table summarizes the technical details of this function.

Return Value: Returns the first key of array if the array is not empty; NULL otherwise.
Version: PHP 7.3.0+


The basic syntax of the array_key_first() function is given with:


The following example shows the array_key_first() function in action.

// Sample array
$persons = array("Harry"=>18, "Clark"=>32, "John"=>24);
// Getting the first key from the persons array
echo array_key_first($persons); // Prints: Harry


The array_key_first() function accepts the following parameters.

Parameter Description
array Required. Specifies the array to be used.

More Examples

Here're some more examples showing how array_key_first() function basically works:

This function can also be used with the indexed array, as shown here:

// Creating an indexed array
$colors[1] = "red";
$colors[2] = "green";
$colors[3] = "blue";

// Getting the first index from the colors array
echo array_key_first($colors); // Prints: 1
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