Noman Haider

PHP Quick Reference Card1.02 string - single byte character sequence. See below.
__DIR__
Variables that have not been assigned a value or have been unset contain the special value NULL. A NULL __CLASS__ assignment to an object variable destroys the object.
__METHOD__
Explicit typecasts are rarely needed in PHP. If required Magic constants use the code inclusion. Copyright©, 2008 BrandsPatch LLC

$x = (#)$y; - where # is one of bool, float, int or string.

Operators

http://www.explainth.at

Operator

Color key on Page 4

Code Structure

Example

Result

3+ 2

5

.

'Explain'.'That!'

'ExplainThat!'

/ «*»

3/2

1.5

%

7%4

3

$s = 'Hello from ';

=

$i = 2

$i set to 2

echo $s;

$i = 2;
$i+=1;

3

$site = 'ExplainThat'; function sayHello(){

//single line comment
}

+= «-=»

Variable Management
Purpose

Return Value

empty

Check if empty?

boolean

floatval

Convert to float

float

.=

s.='That!'

'ExplainThat!'

$s = 'Hello from ';

==1

3=='3'
3==3
3==2

true true false

get_defined_vars List all variables

array

gettype

Verify data type

string1

intval

Convert to int

integer

is_#2

Verify data type

boolean

Stringify for storage string

settype3

Set data type

boolean

strval

function sayHelloEx(){

echo $s.$site;

Method name as class:methodname in included files are evaluated prior to

serialize

s = 'Explain';

global $site;

Current class name

Function

+ «-»

Reusing Code

would cause the contents of mycode.php to be merged | into the current file. Failure to find mycode.php results in a warning. require behaves similarly but throws a fatal ^ error. The #_once versions prevent function redefinition.
~
All labels1 in PHP bear the form $name. name can consist of upper & lowercase letters a-z, extended
ASCII characters from 0x7F to 0xFF, the underscore character, _ and numbers. The first character cannot be a number. Names are case sensitive. $this is a predefined read only variable used to refer to the current object context. There are no limits on name length. Names are case sensitive.
1 Strings used to identify constants, functions, variables & Heredoc

Arrays
Arrays are used to store sequences of related values in a tabular format. PHP has 5 ways of defining an array

$lamp[]='MySQL';$lamp[]='PHP';

The include, require, include_once and require_once $i = 2;$j = 5; keywords facilitate the reuse of PHP code. For instance
&
$i & $j include 'mycode.php';

Nomenclature Rules

-

1 array, boolean, integer, double, string or object
2 # is one of array, bool, float, int, null, object, scalar, string
3 second parameter is a string. See note 1 above
4 behavior inside a function depends on nature of variable being unset

2

$i | $j
$i ^ $j

5

~$i

-3

>»

$i 'LINUX','A'=>'Apache',

7

'M'=>'MySQL','P'=>'PHP');
$lamp = array('LINUX','Apache',
'MySQL','PHP');
$lamp = array();
$lamp[1]='LINUX';$lamp[2]='Apache';
$lamp[3]='MySQL';$lamp[4]='PHP';1

$i = 2;$j = 5

Visibility & Scope
!
($i==2) && !($j true
%2 == 0)
Variables in PHP generally have a single scope – i.e they are always visible. However, user defined functions 1 called loose comparison; 2 called strict comparison have their own local scoping context – i.e. do not have 3 evaluates after use 4 evaluates before use access to variables defined outside the function. A
Constants
reference to $site in sayHello would merely create a define($name,$value,[$ci]) new empty local variable called $site. To access such is used to define a constant named $name with the variables do one of the following scalar value $value. Case insensitive if $ci = TRUE.
Use the global keyword as in sayHelloEx above. constant references do not start with a $
Use the $GLOBALS array - $GLOBALS['site'] constants cannot be altered
Data Types constants are globally accessible
PHP supports four scalar data types
References to undefined constants are treated as string boolean - takes the values TRUE & FALSE literals. PHP defines five magic constants whose value integer - decimal, hexadecimal or octal. e.g. 32, 0x20, depends on where they are used
040. The constants PHP_INT_MAX and
Name
Description
PHP_INT_SIZE provide platform-dependent information. Integer overflow causes silent
__LINE__
Current line number transformation of the variable into a float.
__FILE__
Current file name with path float - Typically IEEE 64 bit with 14 decimal digits.
1

$lamp = array();
$lamp['L']='LINUX';$lamp['A']='Apache';
$lamp['M']='MySQL';$lamp['P']='PHP';
PHP arrays can be associations – i.e. a unique key, (e.g.
'L' above) is associated with each value in the array. For multiple dimensions use arrays within arrays.
Array Manipulation
Function
array_change
_key_case

Description
Guess!

array_chunk($ Returns an array of arrays containing arr,$size,[$f]) $size elements each from $arr.
TRUE for $f preserves keys. arra_fill_keys( $keys,$values)

Create an associative array using
$keys, and $values,.

array_fill($star t,$num,$value) Create an array with $num elements from index $start filled with $value

array_flip($arr
)

Flip values and keys in $arr

array_key_exi

Check for $key in $arr

PHP Quick Reference Card1.02 sts($key,$arr) [$options])

1:0

array_reverse( Reverses element order. $f = TRUE
$arr,[$f])
preserves keys.

Y

2008

y

08

array_values(
$arr)

Returns all values in $arr in a numerically indexed array.

count($arr)

Returns element count

a

am or pm

ksort($arr)

Sorts array using keys

A

AM or PM

g

1-12

G

0-23

h

01-12

H

00-23

i (Minutes)

OR PATHINFO_#
#
= uppercase keys above - into options for more selective results.

00-59

Time

1By default array indices start at 0. Here we force them to start at 1

Date & Time
Function
getDate([$time])

Description
Associative array with current time or $time exploded into
Key

Value

keys
'dirname',
'basename',
'extension' & 'filename'.

dirname($fname)

Counterpart of basename above

glob($pattern,
[$flags])

Returns array of all filenames matching $pattern. OR GLOB_# flags for more selectivity
# Flag

Purpose

0-59

s(Seconds)

0-59

U

0-23
1(!)-31

e

0(Sun)-6(Sat)

P

∆ to GMT

mon

1(!)-12

year

e.g 2008

yday

0(!)-365

Only folders
Stop on error

Europe/Paris

wday

Expand {a,b,c} and match

ONLYDIR

Timezone

mday

As is list

BRACE

UNIX Epoch

hours

NOSORT

00-59

minutes

Add slash

ERR

seconds

MARK

is_#($name)
# = dir or file

is $name a folder or a file?

chdir($dname)

Change current directory. FALSE on failure.

closedir($dhandle)

Closes directory opened earlier using opendir.

Linefeed, 0x0A

getcwd()

Get current directory

\r

Carriage Return, 0x0D

mkdir($dname,
[$mode,$recurse])

\t

Tab, 0x09

\v

Vertical tab, 0x0B

Makes directory $dname. $mode defaults to 0777 – ignored on
Windows. $recurse forces all directories in $dname to be created checkdate($month, Validates date for $year between
$day,$year)
1 & 32767

\f

Form feed, 0x0C

opendir($dname)

\\

Backslash

Opens $dname handle. date($format,
[$time])

\$

Dollar sign

readdir($dhandle)

Reads next filename from open directory. \”

Double quote
Char in hexadecimal

rewinddir($dhandl
e)

Guess!

\x00 - \xFF

rmdir($dname)

Attempts to delete $dname – subject to permissions. FALSE on failure

scandir($dname,
[$order])

Returns array of files in $dname.
Provide
$order
=
1 for descending name sort.

UNIX Epoch time

Escape Sequences

weekday

SundaySaturday

month

JanuaryDecember

0

UNIX Epoch

Formats current time or $time using $format.
Format Char

time()

Example

Day

Sequence
\n

File System

d

01-31

j

1-31

D

Mon

l(l.c. L)

Monday

N

1(Mon)

S

Suffixes st, nd etc. Use with j

w

0(Sun)

z

0-365

Function

file_exists($fname) Does $fname exist? Works with files & folders filesize($fname) Guess?

fileatime($fname)

When was the file accessed?
(UNIX time)

chmod($fname,
$mode)

Change access rights to file
$fname. $mode is an octal number in the format 0OGW where O = Owner, G = User group for Owner & W = the world,
i.e. everyone else. Individual digits are made up by adding the desired rights as listed below

Week of year

Month
F

January

m

Value

01-12

M

Description

basename($fname, Filename minus path – and
[$suffix])
extension if $suffix is provided

Week
W

Meaning

Jan

n t fclose($fhandle)

Close fopen'd file

fopen($fname,
$mode)1

Opens$fname. $mode can be
Mode

Meaning

r1

Read

r+1

Read/Write

w1,2,3

Write

w+1,2,3 Read/ Write

Year)?

Execute

a3,4

Write

Write

a+3,4

Read/Write

4

Days in month

(Leap

rename($old,$new) Guess!

2

1-12

Read

x1,3,5

Write

x+1,3,5

Read/Write

e.g. 0644 means read/write rights for owner & just read for others. pathinfo($fname, Returns associative array with

2

returns

disk_free_space($ Guess! dname) 1

Year
L

Right

and

1File pointer at BOF 2Truncate file to zero length 3Create file if required 4File pointer

PHP Quick Reference Card1.02

Specify an additional b (binary),
e.g. 'wb' for all write modes to prevent CR/LF character translation. Always specify b with all binary files, e.g. images. file_get_contents( $fname)1

Reads contents of $fname into a string. fread($fhandle,
$len)

Read to EOF or $len bytes from file opened for reading. fopen the file with 'b' in the mode flag.

fruncate($fhandle,
$size)

Truncates file open for writing.
Adds null bytes if $size > filesize.

fwrite($fhandle,
$str,[$len])

Writes $str to file opened for writing. Stops at $len if $str length is greater.

file_put_contents(
$fname,$data,
[$flags])

$num to e or $base

pi()

Approx value for π

pow($num,$base)

$num$base

rad2deg($rad)

Radians to degrees

rand([$min],$max)

Random value 0/$min.. $max.

$x = 0);
}
function forLoop($num){ for ($i=0;$i

Miscellanea
Warning – thoughtless use of the features described here could seriously damage your server installation.
The prepend operator, @, can be used with constants, variables, function calls, eval and include to suppress error messages.
The backticks operator `returns the results of running a shell command. For instance, `ls` - dir on Windows – would return a directory listing. This can be assigned to a variable or echoed to standard output. Typing 96 while holding down the ALT key is a keyboard layout independent way of entering the ` operator.

eval($expr) evaluates the PHP code provided in the break causes immediate termination of the loop. Loop string $expr. The string must be valid PHP code – statements after continue are skipped and the next inclusive of terminating semicolons. Errors in $expr may cause the parser to die. Code in $expr forms part of the execution of the loop is performed. parent script so variable assignments in $expr are function foreachLoopA(){ retained. foreach($GLOBALS as $key => $value){
PHP in HTML echo $key.'='.$value.'';
The safest way to embed PHP code in HTML is to
}
delimit it using the tag pair. Other syntax
}
exist but are not accepted by all web servers. The function foreachLoopB(){ resulting file should be saved with the extension .PHP. foreach($_SERVER as $value) echo $value.'';

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