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11/12/2018

PHP - Advanced Basics

Advanced Integers

Official doc : Integers
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$a = 1234; // decimal number
$a = -123; // a negative number
$a = 0123; // octal number (equivalent to 83 decimal)
$a = 0x1A; // hexadecimal number (equivalent to 26 decimal)
$a = 0b11111111; // binary number (equivalent to 255 decimal)

Advanced String

Nowdoc

Official doc : Nowdoc
Nowdocs are to single-quoted strings what heredocs are to double-quoted strings. A nowdoc is specified similarly to a heredoc, but no parsing is done inside a nowdoc. The construct is ideal for embedding PHP code or other large blocks of text without the need for escaping. It shares some features in common with the SGML construct, in that it declares a block of text which is not for parsing.

Heredoc

Official doc : Heredoc
A third way to delimit strings is the heredoc syntax: <<<. After this operator, an identifier is provided, then a newline. The string itself follows, and then the same identifier again to close the quotation.

Double quoted

Official doc : Double quoted
Sequence Meaning
\n linefeed (LF or 0x0A (10) in ASCII)
\r carriage return (CR or 0x0D (13) in ASCII)
\t horizontal tab (HT or 0x09 (9) in ASCII)
\v vertical tab (VT or 0x0B (11) in ASCII) (since PHP 5.2.5)
\e escape (ESC or 0x1B (27) in ASCII) (since PHP 5.4.4)
\f form feed (FF or 0x0C (12) in ASCII) (since PHP 5.2.5)
\\ backslash
\$ dollar sign
\" double-quote
\[0-7]{1,3} the sequence of characters matching the regular expression is a character in octal notation, which silently overflows to fit in a byte (e.g. "\400" === "\000")
\x[0-9A-Fa-f]{1,2} the sequence of characters matching the regular expression is a character in hexadecimal notation
\u{[0-9A-Fa-f]+} the sequence of characters matching the regular expression is a Unicode codepoint, which will be output to the string as that codepoint's UTF-8 representation (added in PHP 7.0.0)

Variables

Advanced Variables

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#array declaration
$array = [];

#push to array
$array[] = 'new entry';

#secure variable in string
echo "${variable[0]}";

#dynamic variable name
echo ${'variable' . $i};

#special assign variable with numeric name 
${0} = 'test';

#dynamic variable
$$var;

Assignment by Reference

Official doc : Assignment by Reference
Assignment by reference is also supported, using the "$var = &$othervar;" syntax. Assignment by reference means that both variables end up pointing at the same data, and nothing is copied anywhere.

Superglobals Variables

Official doc : Superglobals Variables Superglobals are built-in variables that are always available in all scopes
  • $GLOBALS
  • $_SERVER
  • $_GET
  • $_POST
  • $_FILES
  • $_COOKIE
  • $_SESSION
  • $_REQUEST
  • $_ENV

PHP Loose/Stric type comparison

Official doc : PHP type comparison tables
Loose comparisons with ==
TRUE FALSE 1 0 -1 "1" "0" "-1" NULL array() "php" ""
TRUE TRUE FALSE TRUE FALSE TRUE TRUE FALSE TRUE FALSE FALSE TRUE FALSE
FALSE FALSE TRUE FALSE TRUE FALSE FALSE TRUE FALSE TRUE TRUE FALSE TRUE
1 TRUE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE
0 FALSE TRUE FALSE TRUE FALSE FALSE TRUE FALSE TRUE FALSE TRUE TRUE
-1 TRUE FALSE FALSE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE
"1" TRUE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE
"0" FALSE TRUE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
"-1" TRUE FALSE FALSE FALSE TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE
NULL FALSE TRUE FALSE TRUE FALSE FALSE FALSE FALSE TRUE TRUE FALSE TRUE
array() FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE TRUE TRUE FALSE FALSE
"php" TRUE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE TRUE FALSE
"" FALSE TRUE FALSE TRUE FALSE FALSE FALSE FALSE TRUE FALSE FALSE TRUE


Strict comparisons with ===
TRUE FALSE 1 0 -1 "1" "0" "-1" NULL array() "php" ""
TRUE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
1 FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
0 FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
-1 FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
"1" FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE FALSE
"0" FALSE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
"-1" FALSE FALSE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE
NULL FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE
array() FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE
"php" FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE TRUE FALSE
"" FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE TRUE

Alternative Control Structures syntax

if/else

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if ( condition ) : statement; endif;
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if ( condition ) : 
	statement1; 
else:
	statement2;
endif;
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condition ? ifStatementIf : elseStatement;

switch

multiple condition for same statement copy to clipboard
switch (testedValue) {
	case condition1:
	case condition2: statement1;break;
	case condition3: statement3;break;
	default: defaultStatement;
}
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switch (testedValue) :
	case condition1:
	case condition2: statement1;break;
	case condition3: statement3;break;
	default: defaultStatement;
endswitch

isset shorthand

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$foo = $var??'default value';

	#shorthand for
$foo = isset($var)? $var : 'default value';

Functions

Functions Coercive mode

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function foo (string ...$args){
	//$args is an array with all arguments passed
	print_r($args);
};

Anonymous functions

Official doc : Anonymous functions
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$foo = function($arg){ return $arg; };

echo $foo('arg');

Typed anonymous functions with return type and external variable with Assignment by reference

Official doc : functions returning values
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$externalVar = true;

$foo = function( string $arg ) use ( bool &$externalVar ) : ?string
{
	$externalVar = false;
	return $externalVar ? $arg : null;
};

// will echo false
echo $externalVar ? 'true' : 'false';

// will echo true
echo $foo('arg')===null ? 'true' : 'false';

Using namespaces: Aliasing/Importing

Official doc : Using namespaces: Aliasing/Importing
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use some\namespace\{ClassA, ClassB, ClassC as C};
use some\namespace\{ClassA, ClassB, ClassC as C};
use function some\namespace\{fn_a, fn_b, fn_c};
use const some\namespace\{ConstA, ConstB, ConstC};

Exeptions

Official doc : Exeptions
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function doSomething(){
    // throwing an custom exception
    throw new Exception('Exeption message');
}

//trying to do something	
try { doSomething();}
//Catching exception if throwed
catch (Exception $exception) {
    var_dump($exception->getMessage());
}

Exeptions

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Error
  ArithmeticError
	DivisionByZeroError
  AssertionError
  ParseError
  TypeError
	ArgumentCountError
Exception
  ClosedGeneratorException
  DOMException
  ErrorException
  IntlException
  LogicException
	BadFunctionCallException
	  BadMethodCallException
	DomainException
	InvalidArgumentException
	LengthException
	OutOfRangeException
  PharException
  ReflectionException
  RuntimeException
	OutOfBoundsException
	OverflowException
	PDOException
	RangeException
	UnderflowException
	UnexpectedValueException
  SodiumException
Exeptions list tool
Exeptions list by php version
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