MERGES the elements of one or more ARRAYS together so that the values of one are appended to the end of the previous one.
<?php
arr array_merge ( [ arr $array2, ..., $arrayN ] )
where,
$array1 = The first ARRAY of the list of ARRAYS to merge
$array2 = The second ARRAY of the list of ARRAYS to merge
. . . . . . . . . . .
$arrayN = The last ARRAY of the list of ARRAYS to merge
?>
EXERCISE
<?php
$nbr01a = [ 1, 2, 3, 4, 5, 6, 7 ];
$nbr01b = [ 8, 9, 10 ];
$nbr01c = [ 11, 12, 13, 14, 15 ];
echo 'FIRST ARRAY<br><pre>';
print_r($nbr01a);
echo '</pre><br><br>';
echo 'SECOND ARRAY<br><pre>';
print_r($nbr01b);
echo '</pre><br><br>';
echo 'THIRD ARRAY<br><pre>';
print_r($nbr01c);
echo '</pre><br><br>';
echo 'ARRAY after array_merge<br><br>';
$nbr01abc = array_merge ($nbr01a, $nbr01b, $nbr01c);
echo '<pre>';
print_r($nbr01abc);
echo '</pre><br><br>';
?>
EXERCISE
<?php
$nbr02a = [ 'one', 'two', 'three', 'four' ];
$nbr02b = [ 'five', 'six', 'seven' ];
$nbr02c = [ ];
echo 'FIRST ARRAY<br><pre>';
print_r($nbr02a);
echo '</pre><br><br>';
echo 'SECOND ARRAY<br><pre>';
print_r($nbr02b);
echo '</pre><br><br>';
echo 'THIRD ARRAY<br><pre>';
print_r($nbr02c);
echo '</pre><br><br>';
echo 'ARRAY after array_merge<br><br>';
$nbr02abc = array_merge ($nbr02a, $nbr02b, $nbr02c);
echo '<pre>';
print_r($nbr02abc);
echo '</pre><br><br>';
?>
EXERCISE
<?php
$nbr03a = [ ];
$nbr03b = [ ];
$nbr03c = [ ];
echo 'FIRST ARRAY<br><pre>';
print_r($nbr03a);
echo '</pre><br><br>';
echo 'SECOND ARRAY<br><pre>';
print_r($nbr03b);
echo '</pre><br><br>';
echo 'THIRD ARRAY<br><pre>';
print_r($nbr03c);
echo '</pre><br><br>';
echo 'ARRAY after array_merge<br><br>';
$nbr03abc = array_merge ($nbr03a, $nbr03b, $nbr03c);
echo '<pre>';
print_r($nbr03abc);
echo '</pre><br><br>';
?>
EXERCISE
<?php
$nbr04a = [ ];
echo 'UNIQUE ARRAY<br><pre>';
print_r($nbr04a);
echo '</pre><br><br>';
echo 'ARRAY after array_merge<br><br>';
$nbr04abc = array_merge ($nbr04a);
echo '<pre>';
print_r($nbr04abc);
echo '</pre>';
?>
EXERCISE
<?php
$arrm05a = array("R" => "RED",
"G" => "GREEN",
"B" => "BLUE");
$arrm05b = array("H" => "HUE",
"S" => "SATURATION",
"K" => "BLACK");
echo 'INITIAL ARRAYS:<br><pre>';
print_r($arrm05a);
echo '<br><br>';
print_r($arrm05b);
echo '</pre>';
$arrm05ab = array_merge($arrm05a, $arrm05b);
echo '<br><br><br>ARRAY atter array_merge:<br><pre>';
print_r($arrm05ab);
echo '</pre>';
?>
EXERCISE
<?php
$date06 = date(DateTimeInterface::RFC850);
$arrm06a = [ $date06, 'countries' => [ 'Brasil', 'Portugal' ] ];
$arrm06b = [ 'continents' => [ 'South America', 'Europe' ] ];
echo '<br><br>INITIAL ARRAYS:<br><pre>';
print_r($arrm06a);
echo '<br><br>';
print_r($arrm06b);
echo '</pre><br><br>';
$arrm06ab = array_merge($arrm06a, $arrm06b);
echo '<br><br><br>RESULTING ARRAY:<br><pre>';
print_r($arrm06ab);
echo '</pre><br><br>';
?>
EXERCISE
<?php
$arrm07a = [ 'countries' => [ 'Brasil', 'Portugal' ] ];
$arrm07b = [ 'countries' => [ 'Argentina', 'Espanha' ] ];
echo 'INITIAL ARRAYS:<br><pre>';
print_r($arrm07a);
echo '</pre><br><br><pre>';
print_r($arrm07b);
$arrm07ab = array_merge($arrm07a, $arrm07b);
echo '<br><br><br>RESULTING ARRAY:<br><pre>';
print_r($arrm07ab);
echo '</pre>';
?>
EXERCISE
<?php
setlocale(LC_ALL, 'de-DE', 'de_DE');
// Only in PHP versions below 8.0.XX.
echo "Testing basic functionality:<br><br>";
$begin_array = array(
array(),
array( 1 => "string"),
array( "" => "string"),
array( -2.44444 => 12),
array( "a" => 1, "b" => -2.344, "b" => "string",
"c" => NULL, "d" => -2.344),
array( 4 => 1, 3 => -2.344,
"3" => "string", "2" => NULL,1 => -2.344),
array( NULL, 1.23 => "Hi", "string" => "hello",
array("" => "World", "-2.34" => "a", "0" => "b"))
);
$end_array = array(
array(),
array( 1 => "string"),
array( "" => "string"),
array( -2.44444 => 12),
array( "a" => 1, "b" => -2.344, "b" => "string",
"c" => NULL, "d" => -2.344),
array( 4 => 1, 3 => -2.344, "3" => "string",
"2" => NULL, 1=> -2.344),
array( NULL, 1.23 => "Hi", "string" => "hello",
array("" => "World", "-2.34" => "a", "0" => "b"))
);
echo 'First ARRAY:<br>';
var_dump($begin_array);
echo '<br><br>End ARRAY:<br>';
var_dump($end_array);
/* loop through to merge two arrays */
$count_outer = 0;
foreach($begin_array as $first) {
echo "<br><br>Iteration: $count_outer<br>";
$count_inner = 0;
foreach($end_array as $second) {
echo "<br>Inner iteration: $count_inner
of Iteration: $count_outer<br>";
$result = array_merge($first, $second);
print_r($result);
$count_inner++;
}
$count_outer++;
}
echo "<br><br><br>Testing with three or more arrays:<br>";
var_dump( array_merge( $end_array[0],
$end_array[5],
$end_array[4],
$end_array[6]
)
);
echo '<br><br>';
var_dump( array_merge( $end_array[0],
$end_array[5],
array("array on fly"),
array("nullarray" => array())
)
);
echo "<br><br><br>Testing single array argument:<br><br>";
/* Empty array */
var_dump(array_merge(array()));
echo '<br><br>';
/* associative array with string keys,
which will not be re-indexed */
var_dump(array_merge($begin_array[4]));
echo '<br><br>';
/* associative array with numeric keys,
which will be re-indexed */
var_dump(array_merge($begin_array[5]));
echo '<br><br>';
/* associative array with mixed keys
and sub-array as element */
var_dump(array_merge($begin_array[6]));
echo "<br><br><br>Testing array_merge() with typecasting non-array to array:<br>";
var_dump(array_merge($begin_array[4], (array)"type1",
(array)10, (array)12.34));
echo "<br><br><br>Testing array_merge without any arguments:<br>";
var_dump(array_merge());
?>
EXERCISE
<?php
/*
* Test basic functionality of array_merge()
*/
echo "Testing basic functionality:<br><br>";
//indexed array
$array1 = array ('zero', 'one', 'two');
//associative array
$array2 = array ('a' => 1, 'b' => 2, 'c' => 3);
echo 'The given ARRAY(1)<br>';
print_r($array1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($array2);
echo '<br><br>Merging 1 to 2:<br>';
var_dump(array_merge($array1, $array2));
echo '<br><br>Merging 2 to 1:<br>';
var_dump(array_merge($array2, $array1));
?>
EXERCISE
<?php
/*
* Check the position of the
* internal array pointer
* after calling array_merge().
* This test is also passing more than
* two arguments to array_merge().
*/
echo "Testing usage variations:<br><br>";
$arr1 = array ('zero', 'one', 'two');
$arr2 = array ('zero', 'un', 'deux');
$arr3 = array ('null', 'eins', 'zwei');
echo 'The given ARRAY(1)<br>';
print_r($arr1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($arr2);
echo '<br><br>The given ARRAY(3)<br>';
print_r($arr3);
echo "<br><br>Call array_merge():<br>";
var_dump($result = array_merge($arr1, $arr2, $arr3));
echo "<br><br>Position of Internal Pointer in Result:<br>";
echo key($result) . " => " . current($result) . "<br>";
echo "<br>Position of Internal Pointer in Original Array:<br><br>";
echo "\$arr1: ";
echo key($arr1) . " => " . current ($arr1) . "<br>";
echo "\$arr2: ";
echo key($arr2) . " => " . current ($arr2) . "<br>";
echo "\$arr3: ";
echo key($arr3) . " => " . current ($arr3) . "<br>";
?>
EXERCISE
<?php
/*
* Pass an array with different
* data types as keys to test how array_merge
* adds it onto an existing array
*/
echo "Testing usage variations:<br><br>";
// Initialise function arguments
// not being substituted
$arr = array ('one' => 1, 'two' => 2);
//get an unset variable
$unset_var = 10;
unset ($unset_var);
// heredoc string
$heredoc = <<<EOT
hello world
EOT;
// arrays with keys as different
// data types to be passed as $input
$inputs = array(
// int data
/*1*/ 'int' => array(
0 => 'zero',
1 => 'one',
12345 => 'positive',
-2345 => 'negative',
),
// float data
/*2*/ 'float' => array(
10.5 => 'positive',
-10.5 => 'negative',
.5 => 'half',
),
/*3*/ 'extreme floats' => array(
12.3456789000e10 => 'large',
12.3456789000E-10 => 'small',
),
// null data
/*4*/ 'null uppercase' => array(
NULL => 'null 1',
),
/*5*/ 'null lowercase' => array(
null => 'null 2',
),
// boolean data
/*6*/ 'bool lowercase' => array(
true => 'lowert',
false => 'lowerf',
),
/*7*/ 'bool uppercase' => array(
TRUE => 'uppert',
FALSE => 'upperf',
),
// empty data
/*8*/ 'empty double quotes' => array(
"" => 'emptyd',
),
/*9*/ 'empty single quotes' => array(
'' => 'emptys',
),
// string data
/*10*/ 'string' => array(
"stringd" => 'stringd',
'strings' => 'strings',
$heredoc => 'stringh',
),
// undefined data
/*11*/ 'undefined' => array(
@$undefined_var => 'undefined',
),
// unset data
/*12*/ 'unset' => array(
@$unset_var => 'unset',
),
);
// loop through each element of
// $inputs to check the behavior of array_merge
$iterator = 1;
foreach($inputs as $key => $input) {
echo "<br><br>Iteration $iterator: $key data<br><br>";
var_dump( array_merge($input, $arr) );
var_dump( array_merge($arr, $input) );
$iterator++;
};
?>
EXERCISE
<?php
/*
* Pass array_merge() arrays with
* only numeric keys to test behaviour.
* $arr2 contains a duplicate element to $arr1.
*/
echo "Testing usage variations:<br><br>";
//numeric keys
$arr1 = array('zero', 'one', 'two', 'three');
$arr2 = array(1 => 'one', 20 => 'twenty', 30 => 'thirty');
echo 'The given ARRAY(1)<br>';
print_r($arr1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($arr2);
echo '<br><br>Merging 1 to 2:<br>';
var_dump(array_merge($arr1, $arr2));
echo '<br><br>Merging 2 to 1:<br>';
var_dump(array_merge($arr2, $arr1));
?>
EXERCISE
<?php
/*
* Pass array_merge arrays with
* string keys to test behaviour.
* $arr2 has a duplicate key to $arr1
*/
echo "Testing usage variations:<br><br>";
//string keys
$arr1 = array('zero' => 'zero', 'one' => 'un', 'two' => 'deux');
$arr2 = array('zero' => 'zero', 'un' => 'eins', 'deux' => 'zwei');
echo 'The given ARRAY(1)<br>';
print_r($arr1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($arr2);
echo '<br><br>Merging 1 to 2:<br>';
var_dump(array_merge($arr1, $arr2));
echo '<br><br>Merging 2 to 1:<br>';
var_dump(array_merge($arr2, $arr1));
?>
EXERCISE
<?php
/*
* Pass array_merge() arrays
* with mixed keys to test how it
* attaches them to existing arrays
*/
echo "Testing usage variations:<br><br>";
//mixed keys
$arr1 = array('zero', 20 => 'twenty', 'thirty' => 30, true => 'bool');
$arr2 = array(0, 1, 2, null => 'null', 1.234E-10 => 'float');
var_dump(array_merge($arr1, $arr2));
var_dump(array_merge($arr2, $arr1));
echo 'The given ARRAY(1)<br>';
print_r($arr1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($arr2);
echo '<br><br>Merging 1 to 2:<br>';
var_dump(array_merge($arr1, $arr2));
echo '<br><br>Merging 2 to 1:<br>';
var_dump(array_merge($arr2, $arr1));
?>
EXERCISE
<?php
/*
* Test array_merge() with
* multi-dimensional arrays
*/
echo "Testing usage variations:<br><br>";
$arr1 = array('zero', 'one', 'two', array(0));
$arr2 = array(1, 2, 3);
echo 'The given ARRAY(1)<br>';
print_r($arr1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($arr2);
echo "<br><br>Merge a two-dimensional and a one-dimensional array:<br><br>";
var_dump(array_merge($arr1, $arr2));
echo "<br><br>Merge an array and a sub-array:<br>";
var_dump(array_merge($arr1[3], $arr2));
echo '<br><br>';
var_dump(array_merge($arr2, $arr1[3]));
?>
EXERCISE
<?php
/* Test array_merge() when:
* 1. Passed an array made up of
* referenced variables
* 2. Passed an array as the first argument
* and a reference to that array as the second.
*/
echo "Testing usage variations:<br><br>";
$val1 = 'foo';
$val2 = 'bar';
$val3 = 'baz';
$arr1 = array(&$val1, &$val2, &$val3);
$arr2 = array('key1' => 'val1', 'key2' => 'val2', 'key3' => 'val3');
echo 'The given ARRAY(1)<br>';
print_r($arr1);
echo '<br><br>The given ARRAY(2)<br>';
print_r($arr2);
echo "<br><br>Merge an array made up of<br>
referenced variables to an associative array:<br>";
var_dump(array_merge($arr1, $arr2));
echo '<br><br>';
var_dump(array_merge($arr2, $arr1));
$val2 = 'hello world';
echo "<br><br>Change \$val2:<br>";
var_dump(array_merge($arr1, $arr2));
echo '<br><br>';
var_dump(array_merge($arr2, $arr1));
?>