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PHP Array Operators
Introduction
PHP defines following set of symbols to be used as operators on array data types
| Symbol | Example | Name | Result |
|---|---|---|---|
| + | $a + $b | Union | Union of $a and $b. |
| == | $a == $b | Equality | TRUE if $a and $b have the same key/value pairs. |
| === | $a === $b | Identity | TRUE if $a and $b have the same key/value pairs in the same order and of the same types. |
| != | $a != $b | Inequality | TRUE if $a is not equal to $b. |
| <> | $a <> $b | Inequality | TRUE if $a is not equal to $b. |
| !== | $a !== $b | Non-identity | TRUE if $a is not identical to $b. |
Union of arrays
The Union operator appends the right-hand array appended to left-hand array. ; If a key exists in both arrays, the elements from the left-hand array will be used, and the matching elements from the right-hand array will be ignored.
Following example shows use of define() function to define constants
Example
<?php
$arr1=array("phy"=>70, "che"=>80, "math"=>90);
$arr2=array("Eng"=>70, "Bio"=>80,"CompSci"=>90);
$arr3=$arr1+$arr2;
var_dump($arr3);
?>Output
Following result will be displayed
array(6) {
["phy"]=>
int(70)
["che"]=>
int(80)
["math"]=>
int(90)
["Eng"]=>
int(70)
["Bio"]=>
int(80)
["CompSci"]=>
int(90)
}comparison of arrays
Two arrays are said to be equal if they have same key-value pairs. Following example has an indexed array and other associative array with keys corresponding to index of elements in first. Hence both are equal
Example
<?php $arr1=array(0=>70, 2=>80, 1=>90); $arr2=array(70,90,80); var_dump ($arr1==$arr2); var_dump ($arr2!=$arr1); ?>
Output
Following result will be displayed
bool(true) bool(false)
Identity operators
Arrays are identical if and only if both of them have same set of key-value pairs and in same order
Example
<?php $arr1=array(0=>70, 1=>80, 2=>90); $arr2=array(70,90,80); var_dump ($arr1===$arr2); $arr3=[70,80,90]; var_dump ($arr3===$arr1); ?>
Output
Following result will be displayed
bool(false) bool(true)
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