Introduction to php's array equality array Operators

How can we determine that two arrays are equal? In fact, it is very simple. You can use = OR =.

The php manual describes the following,

Example name result
$ A + $ B join $ a and $ B.
$ A = $ B is equal. If $ a and $ B have the same key/value pair, the value is TRUE.
$ A ===$ B. TRUE if $ a and $ B have the same key/value pairs and the order and type are the same.
$! = $ B: TRUE if $ a is not equal to $ B.
$ A <> $ B: TRUE if $ a is not equal to $ B.
$! = $ B incomplete. If $ a is not all equal to $ B, TRUE is returned.
Can the multi-dimensional arrays like array ('K' => array () be judged to be equal using the above method? Of course.

If the array is a digital index, pay attention to it. See the code.

[Php]
<? Php
$ A = array ("apple", "banana ");
$ B = array (1 => "banana", "0" => "apple ");
 
Var_dump ($ a = $ B); // bool (true)
Var_dump ($ a ===$ B); // bool (false)
?>

<? Php
$ A = array ("apple", "banana ");
$ B = array (1 => "banana", "0" => "apple ");

Var_dump ($ a = $ B); // bool (true)
Var_dump ($ a ===$ B); // bool (false)
?>
In addition to the = array operator, there are other methods to judge. For example, array_diff ($ a, $ B) is used to compare the difference sets of two arrays. If the difference set is NULL, It is equal.

Then let's talk about the + plus operator of the array. + The difference between array_merge and array_merge is that when the key is equal, + is used, the left array overwrites the value of the right array. In contrast to array_merge, the following array overwrites the previous one.

[Php]
<? Php
$ A = array ("a" => "apple", "B" => "banana ");
$ B = array ("a" => "pear", "B" => "strawberry", "c" => "cherry ");
 
$ C = $ a + $ B; // Union of $ a and $ B
Echo "Union of \ $ a and \ $ B: \ n ";
Var_dump ($ c );
 
$ C = array_merge ($ a, $ B); // Union of $ B and $
Echo "array_merge of \ $ B and \ $ a: \ n ";
Var_dump ($ c );
?>

<? Php
$ A = array ("a" => "apple", "B" => "banana ");
$ B = array ("a" => "pear", "B" => "strawberry", "c" => "cherry ");

$ C = $ a + $ B; // Union of $ a and $ B
Echo "Union of \ $ a and \ $ B: \ n ";
Var_dump ($ c );

$ C = array_merge ($ a, $ B); // Union of $ B and $
Echo "array_merge of \ $ B and \ $ a: \ n ";
Var_dump ($ c );
?> Output after execution:

[Php]
Union of $ a and $ B:
Array (3 ){
["A"] =>
String (5) "apple"
["B"] =>
String (6) "banana"
["C"] =>
String (6) "cherry"
}
Array_merge of $ B and $:
Array (3 ){
["A"] =>
String (4) "pear"
["B"] =>
String (10) "strawberry"
["C"] =>
String (6) "cherry"
}

Union of $ a and $ B:
Array (3 ){
["A"] =>
String (5) "apple"
["B"] =>
String (6) "banana"
["C"] =>
String (6) "cherry"
}
Array_merge of $ B and $:
Array (3 ){
["A"] =>
String (4) "pear"
["B"] =>
String (10) "strawberry"
["C"] =>
String (6) "cherry"
}