This document provides information about various PHP functions for working with arrays, dates and times, files, numbers, strings, patterns and regular expressions, and sessions. It includes a list of functions for each category along with brief descriptions and examples of parameters.

1. Arrays Regex
array_intersect ereg
array_merge eregi
array_pop ^ Start of string Y 4 digit year 2005 ereg_replace
array_push $ End of string y 2 digit year 05 eregi_replace
array_reverse . F split
Any single character Long month January
array_walk spliti
count (a|b) a or b M Short month Jan preg_match
in_array (...) Group section m Month (leading zeros) 01 to 12 preg_match_all
[abc] Item in range (a or b or c) n Month 1 to 12 preg_replace
Date and Time [^abc] D preg_split
Not in range (not a or b or c) Short day name Mon
date
mktime s White space l Long day name Monday Sessions
strtotime a? Zero or one of a d Day (leading zeros) 01 to 31 session_destroy
time a* Zero or more of a j Day 1 to 31 session_id
a+ One or more of a session_start
Filesystem
clearstatcache a{3} Exactly 3 of a h 12 Hour (leading zeros) 01 to 12 Strings
copy a{3,} 3 or more of a g 12 Hour 1 to 12 addslashes
fclose a{3,6} Between 3 and 6 of a H 24 Hour (leading zeros) 00 to 23 crypt
fgets G echo
Escape character 24 Hour 0 to 23
file explode
filemtime i Minutes (leading zeros) 00 to 59 implode
filesize [:punct:] Any punctuation symbol s Seconds (leading zeros) 00 to 59 md5
file_exists [:space:] Any space character nl2br
fopen [:blank:] w sprintf
Space or tab Day of week 1
0 to 6
fread strip_tags
fwrite z Day of year 0 to 365 stripslashes
is_dir W Week of year 2
1 to 53 stristr
is_file t Days in month 28 to 31 strpos
readfile strrev
i Case-insensitive strstr
Headers s Period matches newline a am or pm strtolower
header m ^ and $ match lines A AM or PM strtoupper
headers_sent U Ungreedy matching B Swatch Internet Time 000 to 999 str_replace
setcookie S substr
e Evaluate replacement Ordinal Suffix st, nd, td, th
trim
Mail x Pattern over several lines
mail T Timezone of machine GMT URLs
Z Timezone offset (seconds) rawurldecode
Numbers O rawurlencode
Difference to GMT (hours) +0200
ceil urldecode
floor I Daylight savings 1 or 0 urlencode
array_push ( array, element )
number_format L Leap year 1 or 0
round in_array ( needle, haystack ) Variables
explode ( separator, string ) empty
U Seconds since Epoch 3
Miscellaneous split ( pattern, string ) is_array
define c ISO 8601 (PHP 5) is_int
preg_split ( pattern, string )
eval r RFC 2822 is_null
exit ereg ( pattern, string ) is_numeric
strpos ( haystack, needle ) 1. date("w"): 0 is Sunday, 6 is Saturday. is_object
Network str_replace ( search, replace, string ) isset
fsockopen serialize
2. Week that overlaps two years belongs to
unserialize
PHP Options year that contains most days of that
ini_get week. Hence week number for 1st January SuperGlobals
ini_restore of a given year can return 53rd week if $_ENV
ini_set r Read $_GET
week belongs to previous year.
phpinfo r+ Read and write, prepend $_POST
date("W", mktime(0, 0, 0, 12, 28, $year)) $_COOKIE
w Write, truncate
Execution always gives correct number of weeks in $_SESSION
w+ Read and write, truncate
exec $year. $_SERVER
a Write, append $_FILES
a+ Read and write, append $_REQUEST
3. The Epoch was the 1st January 1970. $GLOBALS
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