Laravel Collection Public API: keys

keys

The keys method is used to retrieve the keys of all items in the collection. The keys method returns a new Collection instance.

The following code example demonstrates the usage of the keys method:

 1<?php
 2 
 3use Illuminate\Support\Collection;
 4 
 5// Create a new collection.
 6$collection = new Collection([
 7    'first', 'second', 'third'
 8]);
 9 
10$keys = $collection->keys();

After the above code executes, the $keys variable would contain a value similar to the following output:

1object(Illuminate\Support\Collection)[134]
2  protected 'items' =>
3    array (size=3)
4      0 => int 0
5      1 => int 1
6      2 => int 2

The following shows a sample, with output, of a collection containing items represented by an associative array:

 1<?php
 2 
 3use Illuminate\Support\Collection;
 4 
 5// Create a new collection.
 6$collection = new Collection([
 7    'first'  => 'I am first',
 8    'second' => 'I am second',
 9    'third'  => 'I am third'
10]);
11 
12$keys = $collection->keys();

The $keys variable would now contains a value similar to the following output:

1object(Illuminate\Support\Collection)[134]
2  protected 'items' =>
3    array (size=3)
4      0 => string 'first' (length=5)
5      1 => string 'second' (length=6)
6      2 => string 'third' (length=5)

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