(PHP 4, PHP 5, PHP 7, PHP 8)
array_unshift — Prepend one or more elements to the beginning of an array
array_unshift() prepends passed elements to the front
of the array. Note that the list of elements is
prepended as a whole, so that the prepended elements stay in the same
order. All numerical array keys will be modified to start counting from
zero while literal keys won't be changed.
Note:
Resets array's internal pointer to the first element.
arrayThe input array.
valuesThe values to prepend.
Returns the new number of elements in the array.
| Version | Description |
|---|---|
| 7.3.0 | This function can now be called with only one parameter. Formerly, at least two parameters have been required. |
Example #1 array_unshift() example
<?php
$queue = [
"orange",
"banana"
];
array_unshift($queue, "apple", "raspberry");
var_dump($queue);
?>
The above example will output:
array(4) {
[0] =>
string(5) "apple"
[1] =>
string(9) "raspberry"
[2] =>
string(6) "orange"
[3] =>
string(6) "banana"
}
Example #2 Usage with associative arrays
If one associative array is prepended to another associative array, the prepended array is numerically indexed into the former array.
<?php
$foods = [
'apples' => [
'McIntosh' => 'red',
'Granny Smith' => 'green',
],
'oranges' => [
'Navel' => 'orange',
'Valencia' => 'orange',
],
];
$vegetables = [
'lettuce' => [
'Iceberg' => 'green',
'Butterhead' => 'green',
],
'carrots' => [
'Deep Purple Hybrid' => 'purple',
'Imperator' => 'orange',
],
'cucumber' => [
'Kirby' => 'green',
'Gherkin' => 'green',
],
];
array_unshift($foods, $vegetables);
var_dump($foods);
The above example will output:
array(3) {
[0] =>
array(3) {
'lettuce' =>
array(2) {
'Iceberg' =>
string(5) "green"
'Butterhead' =>
string(5) "green"
}
'carrots' =>
array(2) {
'Deep Purple Hybrid' =>
string(6) "purple"
'Imperator' =>
string(6) "orange"
}
'cucumber' =>
array(2) {
'Kirby' =>
string(5) "green"
'Gherkin' =>
string(5) "green"
}
}
'apples' =>
array(2) {
'McIntosh' =>
string(3) "red"
'Granny Smith' =>
string(5) "green"
}
'oranges' =>
array(2) {
'Navel' =>
string(6) "orange"
'Valencia' =>
string(6) "orange"
}
}