PHP Judgment Array Equality array operator Introduction _php tutorial

How can I tell if two arrays are equal? Actually very simple, with = = or = = = can be

The PHP manual describes the following,

Example name result
$a + $b Union of Joint $a and $b.
$a = = $b equal if the $a and $b have the same key/value pairs true.
$a = = = $b congruent if $a and $b have the same key/value pairs and the order and type are the same, TRUE.
$a! = $b is TRUE if the $a does not equal $b.
$a <> $b If the $a is not equal to $b true.
$a!== $b Not equal to TRUE if the $a is not all equals $b.
Can a multidimensional array such as Array (' K ' =>array ()) be judged equal by the above method? Of course I can.

If the array is a numeric index, you should pay attention to it, see the code

[PHP]
$a = Array ("Apple", "banana");
$b = Array (1 = "banana", "0" = "apple");

Var_dump ($a = = $b); BOOL (TRUE)
Var_dump ($a = = = $b); BOOL (FALSE)
?>

$a = Array ("Apple", "banana");
$b = Array (1 = "banana", "0" = "apple");

Var_dump ($a = = $b); BOOL (TRUE)
Var_dump ($a = = = $b); BOOL (FALSE)
?>
In addition to the array operator = =, there are other methods of comparison around to judge. For example, use Array_diff ($a, $b) to compare the difference set of two arrays, which is equal if the difference set is null.

And then say the array's + plus operator. + and Array_merge the difference when encountering equal key, with +, the left array will overwrite the value of the right array, Array_merge instead, the following array overrides the previous.

[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 $a
echo "Array_merge of \ $b and \ $a: \ n";
Var_dump ($c);
?>

$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 $a
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 $a:
Array (3) {
["A"]=>
String (4) "Pear"
["B"]=>
String (Ten) "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 $a:
Array (3) {
["A"]=>
String (4) "Pear"
["B"]=>
String (Ten) "Strawberry"
["C"]=>
String (6) "Cherry"
}

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