PHP Functions
selected php functions
The functions are linked to the part of the PHP manual that describes them.
oOo
most used

fclose
file_get_contents
file_put_contents
filesize
fopen
fread
fwrite

is_dir

mkdir
mysqli_close
mysqli_data_seek
mysqli_free_result
mysqli_num_rows
mysqli_query
mysqli_real_escape_string

require

trim
count

date
dns_check_record

echo
error_log
error_reporting
eval
exec
exit
exp
explode

fflush
file
file_exists
filetype
flock
floor
flush
fmod
fseek
fsockopen
ftp_alloc
ftp_cdup
ftp_chdir
ftp_chmod
ftp_close
ftp_connect
ftp_delete
ftp_exec
ftp_fget
ftp_fput
ftp_get
ftp_get_option
ftp_login
ftp_mdtm
ftp_mkdir
ftp_nb_continue
ftp_nb_fget
ftp_nb_fput
ftp_nb_get
ftp_nb_put
ftp_nlist
ftp_pasv
ftp_put
ftp_pwd
ftp_quit
ftp_raw
ftp_rawlist
ftp_rename
ftp_rmdir
ftp_set_option
ftp_site
ftp_size
ftp_ssl_connect
ftp_systype

get_headers
get_meta_tags
getdate
gethostbyaddr
gethostbyname
gethostbynamel
getimagesize
getlastmod
glob
gmdate
gmmktime

header
headers_list
headers_sent

image_type_to_extension
image_type_to_mime_type
imagealphablending
imageantialias
imagearc
imagechar
imagecharup
imagecolorallocate
imagecolorallocatealpha
imagecolorat
imagecolorclosest
imagecolorclosestalpha
imagecolorclosesthwb
imagecolordeallocate
imagecolorexact
imagecolorexactalpha
imagecolormatch
imagecolorresolve
imagecolorresolvealpha
imagecolorset
imagecolorsforindex
imagecolorstotal
imagecolortransparent
imagecopy
imagecopymerge
imagecopymergegray
imagecopyresampled
imagecopyresized
imagecreate
imagecreatefromgd
imagecreatefromgd2
imagecreatefromgd2part
imagecreatefromgif
imagecreatefromjpeg
imagecreatefrompng
imagecreatefromstring
imagecreatefromwbmp
imagecreatefromxbm
imagecreatefromxpm
imagecreatetruecolor
imagedashedline
imagedestroy
imageellipse
imagefill
imagefilledarc
imagefilledellipse
imagefilledpolygon
imagefilledrectangle
imagefilltoborder
imagefilter
imagefontheight
imagefontwidth
imageftbbox
imagefttext
imagegammacorrect
imagegd
imagegd2
imagegif
imageinterlace
imageistruecolor
imagejpeg
imagelayereffect
imageline
imageloadfont
imagepalettecopy
imagepng
imagepolygon
imagepsbbox
imagepscopyfont
imagepsencodefont
imagepsextendfont
imagepsfreefont
imagepsloadfont
imagepsslantfont
imagepstext
imagerectangle
imagerotate
imagesavealpha
imagesetbrush
imagesetpixel
imagesetstyle
imagesetthickness
imagesettile
imagestring
imagestringup
imagesx
imagesy
imagetruecolortopalette
imagettfbbox
imagettftext
imagetypes
imagewbmp
imagexbm
implode
include
include_once
is_executable
is_file
is_numeric
is_string
is_subclass_of
is_uploaded_file
is_writable
is_writeable
isset
key
krsort
ksort

link
linkinfo
list
localeconv
localtime
log

mail
mailparse_determine_best_xfer_encoding
mailparse_msg_create
mailparse_msg_extract_part
mailparse_msg_extract_part_file
mailparse_msg_free
mailparse_msg_get_part
mailparse_msg_get_part_data
mailparse_msg_get_structure
mailparse_msg_parse
mailparse_msg_parse_file
mailparse_rfc822_parse_addresses
mailparse_stream_encode
mailparse_uudecode_all
main
max

next

opendir
openlog
ord

pack
parse_ini_file
parse_str
parse_url
passthru
pathinfo
php_uname
phpcredits
phpinfo
phpversion
pi
pos
pow
preg_replace
prev
print

rand
range
readdir
readfile
rename
require_once
reset
restore_error_handler
restore_exception_handler
restore_include_path
return
rewind
rewinddir

session_id
session_start
set_time_limit
setcookie
setlocale
sort
sqrt
srand
strip_tags
stripcslashes
stripos
stripslashes
stristr
strlen
strpos
strrchr
strrev
strripos
strrpos
strspn
strstr
strtok
strtolower
strtotime
strtoupper
strtr
strval
substr
system

time

umask
usort

wordwrap
Here is a much longer list of all the documented PHP functions