How to Append One Array to the End of Another One in PHP?

Problem:

You have two arrays. You want to add one array to the end of another array.

Solution:

Here, you’ll see two different ways to append two arrays. Each method has its limitation.

Method 1: Using array_merge() function

The built-in function array_merge() can be used to properly append arrays with numeric keys. The elements of the second array will be added at the end of the first array. See the example-

1 2 3 4 5 6 7 8

<pre> <?php     $language1 = array("C", "C++", "JAVA");     $language2 = array("PHP", "ASP.NET", "PERL");     $language = array_merge($language1, $language2);     print_r($language); ?> </pre>

Output:

1 2 3 4 5 6 7 8 9

Array (   [0] => C   [1] => C++   [2] => JAVA   [3] => PHP   [4] => ASP.NET   [5] => PERL )

Caution: If the both of your input arrays have the same string keys, then the values of the later array will be overwritten the previous one. See the example-

1 2 3 4 5 6 7 8

<pre> <?php     $language1 = array("one" => "C", "two" => "C++", "three" => "JAVA");     $language2 = array("one" => "PHP", "two" => "ASP.NET", "three" => "PERL", "four" => "JSP");     $language = array_merge($language1, $language2);     print_r($language); ?> </pre>

Output:

1 2 3 4 5 6 7

Array (   [one] => PHP   [two] => ASP.NET   [three] => PERL   [four] => JSP )

Recommendation: if the input arrays have numeric keys, use this method to append two arrays without overwriting any element.

Method 2: Using + operator

The + operator(array union operator) can also be used to append two arrays.

If your arrays have different numeric or string keys, you can use + operator to properly append array elements without overwritten any value.

1 2 3 4 5 6 7 8

<pre> <?php     $language1 = array( 0=> "C", 1=> "C++", 2=> "JAVA");     $language2 = array( 3=> "PHP", 4=> "ASP.NET", 5=> "PERL");     $language = $language1 + $language2;     print_r($language); ?> </pre>

Output:

1 2 3 4 5 6 7 8 9

Array (   [0] => C   [1] => C++   [2] => JAVA   [3] => PHP   [4] => ASP.NET   [5] => PERL )

Caution: Regardless of the numeric or string key, the value of the previous array will be overwritten the later one if both arrays have a same key. See an example of different numeric keys-

1 2 3 4 5 6 7 8

<pre> <?php     $language1 = array("C", "C++", "JAVA");     $language2 = array("PHP", "ASP.NET", "PERL");     $language = $language1 + $language2;     print_r($language); ?> </pre>

Output:

1 2 3 4 5 6

Array (   [0] => C   [1] => C++   [2] => JAVA )

Recommendation: If the arrays you want to append have different string keys, you can choose either array_merge() or the + operator to append arrays properly.