COMPUTES the difference between ARRAYS.
<?php
arr array_diff ( arr $array1 , arr $array2 [, arr $arra3, ..., arr $arrayN ] )
where,
$array1 = The first ARRAY to compare from
$array2 = The second ARRAY to compare against
$array3 = The third ARRAY to compare against
$arrayN = The last ARRAY to compare against
?>
EXERCISE
<?php
// Brazilian football, (soccer), teams
$arr01a = [ "Corinthians", "Santos",
"Palmeiras", "São Paulo", "Portuguêsa" ];
$arr01b = [ "Palmeiras", "São Paulo", "Portuguêsa" ];
$arr01c = [ "Vasco", "Botafogo", "Flamengo" ];
echo 'First ARRAY:<br>';
print_r($arr01a);
echo '<br><br>Second ARRAY:<br>';
print_r($arr01b);
echo '<br><br>Third ARRAY:<br>';
print_r($arr01c);
$arr01abc = array_diff($arr01a, $arr01b, $arr01c);
echo '<br><br>After array_diff:<br>';
print_r($arr01abc);
?>
EXERCISE
<?php
// Brazilian football, (soccer), teams
$arr02a = [ "Corinthians", "Santos",
"Palmeiras", "São Paulo", "Portuguêsa" ];
$arr02b = [ "CORINTHIANS", "Palmeiras",
"São Paulo", "Portuguêsa" ];
$arr02c = [ "Vasco", "Botafogo", "Flamengo" ];
print_r($arr02a);
echo '<br><br>';
print_r($arr02b);
echo '<br><br>';
print_r($arr02c);
echo '<br><br>';
$arr02abc = array_diff($arr02a, $arr02b, $arr02c);
print_r($arr02abc);
?>
EXERCISE
<?php
// Brazilian football, (soccer), teams
$arr03a = [ "Santos", "Corinthians",
[ "Palmeiras", "São Paulo", "Portuguêsa" ] ];
$arr03b = [ "Palmeiras", [ "São Paulo", "Portuguêsa" ] ];
$arr03c = [ "Santos", [ "Vasco", "Botafogo", "Flamengo" ] ];
print_r($arr03a);
echo '<br><br>';
print_r($arr03b);
echo '<br><br>';
print_r($arr03c);
echo '<br><br>';
$arr03abc = array_diff($arr03a, $arr03b, $arr03c);
print_r($arr03abc);
?>
EXERCISE
<?php
/*
* Test basic functionality of array_diff
*/
echo "Testing basic functionality:<br><br>";
//Test indexed array with integers as elements
$array_int1 = array (1, 2, 3, 4);
$array_int2 = array (3, 4, 5, 6);
echo 'The given int ARRAY(1):<br>';
var_dump($array_int1);
echo '<br><br>The given int ARRAY(2):<br>';
var_dump($array_int2);
echo "<br><br>Test indexed array with integers as elements:<br>";
var_dump(array_diff($array_int1, $array_int2));
echo '<br><br>';
var_dump(array_diff($array_int2, $array_int1));
//Test indexed array with strings as elements
$array_string1 = array ('one', 'two', 'three', 'four');
$array_string2 = array ('three', 'four', 'five', 'six');
echo '<br><br>The given str ARRAY(1):<br>';
var_dump($array_string1);
echo '<br><br>The given str ARRAY(2):<br>';
var_dump($array_string2);
echo "<br><br>Test indexed array
with strings as elements:<br>";
var_dump(array_diff($array_string1, $array_string2));
echo '<br><br>';
var_dump(array_diff($array_string2, $array_string1));
//Test associative array with strings
//as keys and integers as elements
$array_assoc_int1 = array ('one' => 1, 'two' => 2,
'three' => 3, 'four' => 4);
$array_assoc_int2 = array ('three' => 3,
'four' => 4, 'five' => 5, 'six' => 6);
echo '<br><br>The given str&int ARRAY(1):<br>';
var_dump($array_assoc_int1);
echo '<br><br>The given str&int ARRAY(2):<br>';
var_dump($array_assoc_int2);
echo "<br><br>Test associative array with strings
as keys and integers as elements:<br>";
var_dump(array_diff($array_assoc_int1, $array_assoc_int2));
echo '<br><br>';
var_dump(array_diff($array_assoc_int2, $array_assoc_int1));
//Test associative array with strings as keys and elements
$array_assoc_str1 = array ('one' => 'un', 'two' =>
'deux', 'three' => 'trois', 'four' => 'quatre');
$array_assoc_str2 = array ('three' => 'trois',
'four' => 'quatre', 'five' => 'cinq', 'six' => 'six');
echo '<br><br>The given str&str ARRAY(1):<br>';
var_dump($array_assoc_str1);
echo '<br><br>The given str&str ARRAY(2):<br>';
var_dump($array_assoc_str2);
echo "<br><br>Test associative array with strings
as keys and integers as elements;<br>";
var_dump(array_diff($array_assoc_str1, $array_assoc_str2));
echo '<br><br>';
var_dump(array_diff($array_assoc_str2, $array_assoc_str1));
echo "<br><br>Test array_diff with more than 2 arguments:<br>";
var_dump(array_diff($array_int1, $array_int2,
$array_string1, $array_string2));
?>
EXERCISE
<?php
/*
* Test behaviour of array_diff()
* function with binary input
*/
echo "Testing usage variations;<br><br>";
$array1 = array( b"1",
b"hello",
"world",
"str1" => "hello",
"str2" => "world");
$array2 = array( b"1" => 'hello',
b"world",
"hello",
'test');
echo 'The given str ARRAY(1):<br>';
var_dump($array1);
echo '<br><br>The given str ARRAY(2):<br>';
var_dump($array2);
echo '<br><br>After array_diff($array1, $array2):<br>';
var_dump(array_diff($array1, $array2));
echo '<br><br>After array_diff($array2, $array1):<br>';
var_dump(array_diff($array2, $array1));
?>
EXERCISE
<?php
/*
* Test how array_diff() compares
* indexed arrays containing different
* data types as values in place of $arr1
*/
echo "Testing usage variations:<br>";
// Initialise function arguments
// not being substituted (if any)
$array = array(1, 2);
//get an unset variable
$unset_var = 10;
unset ($unset_var);
//get heredoc
$heredoc = <<<END
This is a heredoc
END;
//array of values to iterate over
$values = array(
/*1*/"empty array" => array(),
/*2*/
"int" => array(
// int data
0,
1,
12345,
-2345),
/*3*/
"float" => array(
// float data
10.5,
-10.5,
12.3456789000e10,
12.3456789000E-10,
.5),
/*4*/
"null" => array(
// null data
NULL,
null),
/*5*/
"boolean" => array(
// boolean data
true,
false,
TRUE,
FALSE),
/*6*/
"empty" => array(
// empty data
"",
''),
/*7*/
"string" => array(
// string data
"string",
'string',
$heredoc),
/*8*/
"binary" => array(
// binary data
b"binary",
(binary)"binary"),
/*9*/
"undefined" => array(
// undefined data
@$undefined_var),
/*10*/
"unset" => array(
// unset data
@$unset_var)
);
// loop through each element of the array for arr1
$iterator = 1;
foreach($values as $value) {
echo "<br><br>Iteration: $iterator<br>";
var_dump( array_diff($value, $array) );
$iterator++;
};
?>
EXERCISE
<?php
/*
* Test how array_diff() compares
* indexed arrays containing different
* data types as values in place of $arr2
*/
echo "Testing array_diff() : usage variations:<br>";
// Initialise function arguments
// not being substituted (if any)
$array = array(1, 2);
//get an unset variable
$unset_var = 10;
unset ($unset_var);
//get heredoc
$heredoc = <<<END
This is a heredoc
END;
//array of values to iterate over
$values = array(
/*1*/"empty array" => array(),
/*2*/
"int" => array(
// int data
0,
1,
12345,
-2345),
/*3*/
"float" => array(
// float data
10.5,
-10.5,
12.3456789000e10,
12.3456789000E-10,
.5),
/*4*/
"null" => array(
// null data
NULL,
null),
/*5*/
"boolean" => array(
// boolean data
true,
false,
TRUE,
FALSE),
/*6*/
"empty" => array(
// empty data
"",
''),
/*7*/
"string" => array(
// string data
"string",
'string',
$heredoc),
/*8*/
"binary" => array(
// binary data
b"binary",
(binary)"binary"),
/*9*/
"undefined" => array(
// undefined data
@$undefined_var),
/*10*/
"unset" => array(
// unset data
@$unset_var)
);
// loop through each element of the array for $arr2
$iterator = 1;
foreach($values as $value) {
echo "<br><br>Iteration: $iterator<br>";
var_dump( array_diff($array, $value) );
$iterator++;
};
?>
EXERCISE
<?php
/*
* Test how array_diff compares
* integers, floats and strings
*/
echo "Testing array_diff() : usage variations:<br><br>";
$arr_int = array(1, 2, 3);
$arr_float = array(1.00, 2.00, 3.00);
$arr_int_str = array('1', '2', '3');
$arr_float_str = array('1.00', '2.00', '3.00');
echo '<u>The given $arr_int:</u><br>';
var_dump($arr_int);
echo '<br><br><u>The given $arr_float:</u><br>';
var_dump($arr_float);
echo '<br><br><u>The given $arr_int_str:</u><br>';
var_dump($arr_int_str);
echo '<br><br><u>The given $arr_float_str:</u><br>';
var_dump($arr_float_str);
print "<br><br><u>Compare integers and floats.</u><br><br>";
echo 'After array_diff($arr_int, $arr_float):<br>';
var_dump(array_diff($arr_int, $arr_float));
echo '<br><br>After array_diff($arr_float, $arr_int):<br>';
var_dump(array_diff($arr_float, $arr_int));
print "<br><br><u>Compare integers and strings
containing an integers.</u><br><br>";
echo 'After array_diff($arr_int, $arr_int_str):<br>';
var_dump(array_diff($arr_int, $arr_int_str));
echo '<br><br>After array_diff($arr_int_str, $arr_int):<br>';
var_dump(array_diff($arr_int_str, $arr_int));
print "<br><br><u>Compare integers and strings
containing floats.</u><br><br>";
echo 'After array_diff($arr_int, $arr_float_str):<br>';
var_dump(array_diff($arr_int, $arr_float_str));
echo '<br><br>After array_diff($arr_float_str, $arr_int):<br>';
var_dump(array_diff($arr_float_str, $arr_int));
print "<br><br><u>Compare floats and strings
containing integers.</u><br><br>";
echo 'After array_diff(array_diff($arr_float, $arr_int_str):<br>';
var_dump(array_diff($arr_float, $arr_int_str));
echo '<br><br>After array_diff($arr_int_str, $arr_float):<br>';
var_dump(array_diff($arr_int_str, $arr_float));
print "<br><br><u>Compare floats and strings
containing floats.</u><br><br>";
echo 'After array_diff(array_diff($arr_float, $arr_float_str):<br>';
var_dump(array_diff($arr_float, $arr_float_str));
echo '<br><br>After array_diff($arr_float_str, $arr_float):<br>';
var_dump(array_diff($arr_float_str, $arr_float));
print "<br><br><u>Compare strings
containing integers and strings
containing floats.</u><br><br>";
echo 'After array_diff(array_diff($arr_int_str, $arr_float_str):<br>';
var_dump(array_diff($arr_int_str, $arr_float_str));
echo '<br><br>After array_diff($arr_float_str, $arr_int_str):<br>';
var_dump(array_diff($arr_float_str, $arr_int_str));
?>
EXERCISE
<?php
/*
* Test that array_diff behaves
* as expected for comparing:
* 1. the order of the array
* 2. duplicate values
* 3. duplicate key names
*/
echo "Testing array_diff() : usage variations:<br><br>";
$array_index = array('a', 'b', 'c', 0 => 'd', 'b');
//duplicate key (0), duplicate value (b)
$array_assoc = array ('2' => 'c',
//same key=>value pair, different order
'1' => 'b',
'0' => 'a',
'b' => '3',
//key and value from array_index swapped
'c' => 2);
//same as above, using integer
echo 'The given ARRAY(1):<br>';
var_dump($array_index);
echo '<br><br>The given ARRAY(2):<br>';
var_dump($array_assoc);
echo '<br><br>After array_diff($array_index, $array_assoc):<br>';
var_dump(array_diff($array_index, $array_assoc));
echo '<br><br>After array_diff($array_assoc, $array_index):<br>';
var_dump(array_diff($array_assoc, $array_index));
?>
EXERCISE
<?php
/*
* Test how array_diff compares arrays that
* 1. Contain referenced variables
* 2. Have been referenced to each other
*/
echo "Testing array_diff() : usage variations:<br><br>";
$a = 'a';
$arr1 = array ("&$a", 'b', 'c');
$arr2 = array (1, 2, 3);
echo "Basic Comparison.<br><br>";
echo 'After array_diff($arr1, $arr2):<br>';
var_dump(array_diff($arr1, $arr2));
echo '<br><br>After array_diff($arr2, $arr1):<br>';
var_dump(array_diff($arr2, $arr1));
$a = 1;
echo "<br><br>\$a changed.<br><br>";
echo 'After array_diff($arr1, $arr2):<br>';
var_dump(array_diff($arr1, $arr2));
echo '<br><br>After array_diff($arr2, $arr1):<br>';
var_dump(array_diff($arr2, $arr1));
$arr2 = &$arr1;
echo "<br><br>Arrays referenced to each other.<br><br>";
echo 'After array_diff($arr1, $arr2):<br>';
var_dump(array_diff($arr1, $arr2));
echo '<br><br>After array_diff($arr2, $arr1):<br>';
var_dump(array_diff($arr2, $arr1));
$arr1 = array('x', 'y', 'z');
echo "<br><br>\$arr1 changed.<br><br>";
echo 'After array_diff($arr1, $arr2):<br>';
var_dump(array_diff($arr1, $arr2));
echo '<br><br>After array_diff($arr2, $arr1):<br>';
var_dump(array_diff($arr2, $arr1));
?>
EXERCISE
<?php
/*
* Test how array_diff() compares
* multidimensional arrays
*/
echo "Testing array_diff() : usage variations:<br><br>";
$array1 = array('sub_array1' => array (1, 2, 3),
'sub_array2' => array ('a', 'b', 'c'));
$array2 = array('sub_arraya' => array (1, 3, 5),
'sub_arrayb' => array ('a', 'z', 'y'));
echo 'The given ARRRAY(1):<br>';
var_dump($array1);
echo '<br><br>The given ARRRAY(2):<br>';
var_dump($array2);
echo "<br><br>Compare two 2-D arrays.<br>";
var_dump(array_diff($array1, $array2));
var_dump(array_diff($array2, $array1));
echo "<br><br>Compare subarrays from two 2-D arrays.<br>";
var_dump(array_diff($array1['sub_array1'],
$array2['sub_arraya']));
var_dump(array_diff($array2['sub_arraya'],
$array1['sub_array1']));
var_dump(array_diff($array1['sub_array2'],
$array2['sub_arrayb']));
var_dump(array_diff($array2['sub_arrayb'],
$array1['sub_array1']));
echo "<br><br>Compare a subarray from one 2-D array
and one 2-D array.<br>";
var_dump(array_diff($array1['sub_array1'], $array2));
var_dump(array_diff($array1, $array2['sub_arraya']));
?>