Miscellaneous

Runtime defined Constants

define("CURRENT\_DATE", date('Y-m-d')); // One possible representation echo CURRENT_DATE; # => 2021-01-05 # => CURRENT\_DATE is: 2021-01-05 echo 'CURRENT\_DATE is: ' . CURRENT_DATE;

fopen() mode

-	-
`r`	Read
`r+`	Read and write, prepend
`w`	Write, truncate
`w+`	Read and write, truncate
`a`	Write, append
`a+`	Read and write, append

Regular expressions

$str = "Visit Quickref.me"; echo preg\_match("/qu/i", $str); # => 1

See: Regex in PHP

Nullsafe Operator

// As of PHP 8.0.0, this line: $result = $repo?->getUser(5)?->name; // Equivalent to the following code: if (is\_null($repo)) { $result = null; } else { $user = $repository->getUser(5); if (is\_null($user)) { $result = null; } else { $result = $user->name; } }

Custom exception

class MyException extends Exception { // do something }

Usage

try { $condition = true; if ($condition) { throw new MyException('bala'); } } catch (MyException $e) { // Handle my exception }

Exception in PHP 8.0

$nullableValue = null; try { $value = $nullableValue ?? throw new InvalidArgumentException(); } catch (InvalidArgumentException) { // Variable is optional // Handle my exception echo "print me!"; }

Basic error handling

try { // Do something } catch (Exception $e) { // Handle exception } finally { echo "Always print!"; }

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