Laravel Collection Public API: zip

zip($items)

The zip method is used to merge the values of the $items array with the values within the Collection at the corresponding index. The zip method produces results that are similar to Python's zip function, and developer's coming from a Python background will recognize the behavior of the zip method. The zip method returns a new Collection instance and does not modify the original collection in any way.

 1<?php
 2 
 3use Illuminate\Support\Collection;
 4 
 5// Create a new collection instance.
 6$collection = new Collection([
 7    1, 2, 3
 8]);
 9 
10// Create a new collection by zipping the original
11// collection with a new array of values.
12$zipped = $collection->zip([
13    4, 5, 6
14]);

After the above code has executed, the $zipped variable will be an instance of Collection and contain a value similar to the following output:

 1object(Illuminate\Support\Collection)[135]
 2  protected 'items' =>
 3    array (size=3)
 4      0 =>
 5        object(Illuminate\Support\Collection)[136]
 6          protected 'items' =>
 7            array (size=2)
 8              0 => int 1
 9              1 => int 4
10      1 =>
11        object(Illuminate\Support\Collection)[137]
12          protected 'items' =>
13            array (size=2)
14              0 => int 2
15              1 => int 5
16      2 =>
17        object(Illuminate\Support\Collection)[138]
18          protected 'items' =>
19            array (size=2)
20              0 => int 3
21              1 => int 6

The zip method can accept multiple arguments, and they can be any data type that can be converted to an array:

 1<?php
 2 
 3use Illuminate\Support\Collection;
 4 
 5// Create a new collection instance.
 6$collection = new Collection([
 7    1, 2, 3
 8]);
 9 
10// Create a new collection instance to use an
11// an argument for the zip method.
12$testCollection = new Collection([
13    7, 8, 9
14]);
15 
16// Notice the call to all() at the end of this
17// method chain to return the array of
18// zipped results
19$zippedResults = $collection->zip(
20    [4, 5, 6],
21    $testCollection,
22    [10, 11],
23    [12, 13, 14, 15]
24)->all();

After the above code has executed, the $zippedResults variable would contain the following value:

 1array (size=4)
 2  0 =>
 3    object(Illuminate\Support\Collection)[137]
 4      protected 'items' =>
 5        array (size=5)
 6          0 => int 1
 7          1 => int 4
 8          2 => int 7
 9          3 => int 10
10          4 => int 12
11  1 =>
12    object(Illuminate\Support\Collection)[138]
13      protected 'items' =>
14        array (size=5)
15          0 => int 2
16          1 => int 5
17          2 => int 8
18          3 => int 11
19          4 => int 13
20  2 =>
21    object(Illuminate\Support\Collection)[139]
22      protected 'items' =>
23        array (size=5)
24          0 => int 3
25          1 => int 6
26          2 => int 9
27          3 => null
28          4 => int 14
29  3 =>
30    object(Illuminate\Support\Collection)[140]
31      protected 'items' =>
32        array (size=5)
33          0 => null
34          1 => null
35          2 => null
36          3 => null
37          4 => int 15

There are a few important things to notice in the above output. The [10, 11] array that was passed as an argument had less items than the other arrays when building the final result. As a result, the value null was used for the fourth item in the third Collection instance The other important thing to notice is a result of the [12, 13, 14, 15] argument having more items that the other arrays.

Because the [12, 13, 14, 15] argument had more items, a new fourth Collection was created as part of the zipped results. All values were set to null, except for the fifth value, which was assigned the value 15.

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