PHP 5 - Online Cheat Sheet

Type: Boolean

Values (case insensitive): TRUE, FALSE, true, false
Casts: (bool), (boolean)
The value -1 is considered TRUE, like any other non-zero (whether negative or positive) number!

Type: Integer

Casts: (int), (integer)
If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead.

Type: String

When a string is specified in double quotes (") the variables are parsed within it.
Converting to string: with cast (string) or strval()
String Functions:
- array explode( string $delimiter , string $string , [ int $limit ] ) - Returns an array of strings, each of which is a substring of string formed by splitting it on boundaries formed by the string delimiter
- string implode( string $glue , array $pieces ) - Join array elements with a glue string
- string htmlentities( string $string , [ int $quote_style , [ string $charset ,[ bool $double_encode ]]] ) - Convert all applicable characters to HTML entities
- string html_entity_decode( string $string , [ int $quote_style , [ string $charset ]] ) - Convert all HTML entities to their applicable characters
- int strlen( string $string ) - Get string length
- string strstr( string $haystack , mixed $needle , [ bool $before_needle ] ) - Find first occurrence of a string
- int strpos( string $haystack , mixed $needle , [ int $offset ] ) - Returns the numeric position of the first occurrence of needle in the haystack string
- string substr( string $string , int $start , [ int $length ] ) - Return part of a string

Type: Array

An array can be created by the array() language construct.
The unset() function allows removing keys from an array.
Converting to array:(array)$scalarValue or array($scalarValue)
Array Functions:
- array array_diff( array $array1 , array $array2 , [ array $ ... ] ) - Compares array1 against array2 and returns the difference
- array array_keys( array $input , [ mixed $search_value ,[ bool $strict ]] ) - Return all the keys of an array
- array array_map( callback $callback , array $arr1 , [ array $... ] ) - Applies the callback to the elements of the given arrays
- bool array_walk( array &$array , callback $funcname ,[ mixed $userdata ] ) - Apply a user function to every member of an array
- array array_merge( array $array1 ,[ array $array2 , [ array $... ]] ) - Merge one or more arrays
- mixed array_pop( array &$array ) - Pop the element off the end of array
- int array_push( array &$array , mixed $var ,[ mixed $... ] ) - Push one or more elements onto the end of array
- mixed array_shift( array &$array ) - Shift an element off the beginning of array
- mixed array_unshift( array &$array , mixed $var , [ mixed $... ] ) - Prepend one or more elements to the beginning of an array
- array array_slice( array $array , int $offset ,[ int $length ,[ bool $preserve_keys ]] ) - Returns the sequence of elements from the array array as specified by the offset and length parameters
- array array_splice( array &$input , int $offset ,[ int $length ,[ mixed $replacement ]] ) - Removes the elements designated by offset and length from the input array, and replaces them with the elements of the replacement array, if supplied
- array in_array( mixed $needle , array $haystack ,[ bool $strict ] ) - Checks if a value exists in an array, searches haystack for needle

Type: Object/Class

To instatiate a class use the new statement.
If a value of any other type is converted to an object, a new instance of the stdClass built-in class is created.
Setting constants inside of class with const keyword.
Class definition:
- general
  1 2
  class SampleClass { }
- abstract - It is not allowed to create an instance of a class that has been defined as abstract
  1 2
  abstract class SampleClass { }
- final - Prevents the class to be extended
  1 2
  final class SampleClass { }

Class members declaration:

static - Declaring class members or methods as static makes them accessible without needing an instantiation of the class

class SampleClass {
        
        public static $class_propery = "foo";
        
        public static class_method() {
                //code here
        }
}

final - Prevents child classes from overriding a method

class SampleClass {
 
        final public class_method() {
                //code here
        }
}

Class members visibility:

public - Public declared items can be accessed everywhere

class SampleClass {
 
        public $class_propery = "foo";
 
        public class_method() {
                //code here
        }
}

private - Private limits visibility only to the class that defines the item

class SampleClass {
 
        private $class_propery = "foo";
 
        private class_method() {
                //code here
        }
}

protected - Protected limits access to inherited and parent classes (and to the class that defines the item)

class SampleClass {
 
        protected $class_propery = "foo";
 
        protected class_method() {
                //code here
        }
}

Date/Time

Functions:
- string date( string $format , [ int $timestamp ] ) - Returns a string formatted according to the given format string using the given integer timestamp or the current time if no timestamp is given
- void date_add( DateTime $object , DateInterval $interval ) - Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
- int mktime( [ int $hour ,[ int $minute ,[ int $second ,[ int $month ,[ int $day ,[ int $year ,[ int $is_dst ]]]]]]] ) - Returns the Unix timestamp corresponding to the arguments given
- int strtotime( string $time ,[ int $now ] ) - The function expects to be given a string containing a US English date format and will try to parse that format into a Unix timestamp
- int time() - Return current Unix timestamp
Date/Time Formats:
- Day
  - d - 01 - 31
  - j - 1 - 31
  - D - Mon - Sun
  - l - Monday - Sunday
- Month
  - M - Jan - Dec
  - F - January - December
  - m - 01 - 12
  - n - 1 - 12
- Year
  - Y - 2003, 2008
  - y - 03, 08
- Time
  - a - am, pm
  - A - AM, PM
  - g - 12 hours - 1 - 12
  - h - 12 hours - 00 - 12
  - H - 24 hours - 00 - 23
  - G - 24 hours - 0 - 23
  - i - minutes - 00 - 59
  - s - seconds - 00 - 59

Predefined Variables

$_SERVER:
- The values in the array are provided by the server, there's no guarantee that all the values will be available on your configuration. In this list you can find the most used values only.
- PHP_SELF - the filename of the currently executing script, relative to the document root
- SERVER_ADDR - the IP address of the server
- SERVER_NAME - the name of the server
- REQUEST_METHOD - which request method was used to access the page: GET, HEAD, POST, PUT
- QUERY_STRING - the query string, if any, via which the page was accessed
- DOCUMENT_ROOT - the document root directory under which the current script is executing
- HTTP_REFERER - the address of the page (if any) which referred the user agent to the current page
- REMOTE_ADDR - the IP address from which the user is viewing the current page
- SCRIPT_FILENAME - the absolute pathname of the currently executing script
- REQUEST_URI - The URI which was given in order to access this page; e.g. /index.html
$_FILES:
- $_FILES['userfile']['name'] - the original name of the file on the client machine
- $_FILES['userfile']['type'] - the mime type of the file, if the browser provided this information
- $_FILES['userfile']['size'] - the size, in bytes, of the uploaded file
- $_FILES['userfile']['tmp_name'] - the temporary filename of the file in which the uploaded file was stored on the server
- $_FILES['userfile']['error'] - The error code associated with this file upload
  - Error codes:
  - UPLOAD_ERR_OK or value 1 - no error
  - UPLOAD_ERR_INI_SIZE or value 2 - the uploaded file exceeds the upload_max_filesize directive in php.ini
  - UPLOAD_ERR_PARTIAL or value 3 - the uploaded file was only partially uploaded
  - UPLOAD_ERR_NO_FILE or value 4 - no file was uploaded
  - UPLOAD_ERR_NO_TMP_DIR or value 5 - missing temporary folder
  - UPLOAD_ERR_CANT_WRITE or value 7 - failed to write file to disk
  - UPLOAD_ERR_EXTENSION or value 8 - file upload stopped by extension