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Make comparisons clearer when type juggling

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Malcolm Fell 2013-06-28 09:03:08 +12:00
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1 changed files with 11 additions and 6 deletions
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@ -111,24 +111,29 @@ echo function_result(); // Output the result of a function call that returns a v
### Assignment ### Assignment
```php ```php
$a = 1; $x = 1;
$b = 2; $y = 2;
$a = $b; // A now contains the same value sa $b $x = $y; // A now contains the same value sa $y
$a = &$b; // A now contains a reference to $b. Changing the value of $a will change the value of $b also, and vice-versa. $x = &$y; // A now contains a reference to $y. Changing the value of $x will change the value of $y also, and vice-versa.
``` ```
### Comparison ### Comparison
```php ```php
// These comparisons will always be true, even if the types aren't the same.
$a == $b // TRUE if $a is equal to $b after type juggling. $a == $b // TRUE if $a is equal to $b after type juggling.
$a === $b // TRUE if $a is equal to $b, and they are of the same type.
$a != $b // TRUE if $a is not equal to $b after type juggling. $a != $b // TRUE if $a is not equal to $b after type juggling.
$a <> $b // TRUE if $a is not equal to $b after type juggling. $a <> $b // TRUE if $a is not equal to $b after type juggling.
$a !== $b // TRUE if $a is not equal to $b, or they are not of the same type.
$a < $b // TRUE if $a is strictly less than $b. $a < $b // TRUE if $a is strictly less than $b.
$a > $b // TRUE if $a is strictly greater than $b. $a > $b // TRUE if $a is strictly greater than $b.
$a <= $b // TRUE if $a is less than or equal to $b. $a <= $b // TRUE if $a is less than or equal to $b.
$a >= $b // TRUE if $a is greater than or equal to $b. $a >= $b // TRUE if $a is greater than or equal to $b.
// The following will only be true the values match and they are the same type.
$a === $b // TRUE if $a is equal to $b, and they are of the same type.
$a !== $b // TRUE if $a is not equal to $b, or they are not of the same type.
1 == '1' // TRUE
1 === '1' // FALSE
``` ```
## [Type Juggling](http://www.php.net/manual/en/language.types.type-juggling.php) ## [Type Juggling](http://www.php.net/manual/en/language.types.type-juggling.php)