Perl built-in functions

Computing: Programming: Perl: built-in functions

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By Type

Arrays

• join(demarc,array) &ndashl joins array elements into one string, using demarc as a seperator string
• split(pattern,string,limit) – splits string into an array (return value) by dividing it wherever pattern is matched
• splice(target,offset,length,source) – combines parts of two arrays (replaces parts of target with source)
• pop(array) – remove/return the last element of array
• push(target,source) – adds elements from source to the end of the array target (opposite of pop())
• reverse(array) – returns an array containing the elements of the input array in reverse order
• sort(array) – returns an array containing the elements of the input array in sorted order
• shift(array) – remove/return the first element of array (opposite of unshift())
• unshift(target,source) – add elements from the array source to the beginning of the array target (opposite of shift())

Dirs

• opendir(dirhandle, dirspec)
• rmdir

Dir Handles

• closedir
• readdir
• rewinddir
• seekdir

Files

• chdir
• chmod
• chown
• chroot
• link
• mkdir
• open(filehandle, filespec)
• readlink
• rename

File Handles

• binmode
• close
• eof
• flock
• getc
• lstat
• read
• seek
• truncate
• write

Numeric

• abs(number)
• exp
• log
• rand
  • srand
• sqrt

Base conversion

• hex
• oct

Trigonometry

• atan2(Y, X) - returns the arctangent of Y/X
• cos
• sin

RegEx

• m/pattern/
• quotemeta
• s/pattern/replacement/egimosx
• tr/search_list/replace_list/cds
• y/search_list/replace_list/cds

String

• chomp
• chop
• crypt
• index
• lc
• lcfirst
• length
• quotemeta
• rindex
• scalar
• substr(source,offset,len) – return len bytes from source after skipping offset characters
• uc
• ucfirst
• unpack

conversion

• int

single-character

• chr(number) - returns the character whose ASCII code is number
• ord(string) - returns the ASCII code of the first character in string

Time

• gmtime
• localtime
• time
• times

Alphabetical

A

• abs(arg) - returns absolute value of arg
• accept()
• alarm($seconds) - sends an alarm signal after $seconds seconds
• atan2($y,$x) - returns the arctangent of $y/$x

B

• bind()
• binmode(filehandle) - sets filehandle to be treated as binary
• bless()

C

• caller()
• chdir()
• chmod()
• chomp()
• chop()
• chown()
• chr()
• chroot()
• close()
• closedir()
• connect()
• cos()
• crypt()

D

• dbmclose()
• dbmopen()
• defined()
• delete()
• die()
• do subroutine
• dump()

E

• each()
• endgrent
• endhostent
• endnetent
• endprotoent
• endpwent
• endservent
• eof()
• eval()
• exec()
• exists($assoc($key)) - returns TRUE if $key exists within the hash $assoc. Doesn't work with dbm hashes.
• exit()
• exp()

F

• fcntl()
• fileno()
• flock()
• fork
• format
• formline()

G

• getc()
• getgrent
• getgrgid()
• getgrnam()
• gethostbyaddr()
• gethostbyname()
• gethostent
• getlogin
• getnetbyaddr()
• getnetbyname()
• getnetent
• getpeername()
• getpgrp()
• getppid
• getpriority()
• getprotobyname()
• getprotobynumber()
• getprotoent
• getpwent
• getpwnam()
• getpwuid()
• getserverbyname()
• getserverbyport()
• getservent
• getsockname()
• getsockopt()
• glob()
• gmtime()
• goto()
• grep()

H

• hex()

I

• index()
• int()
• ioctl()

J

• join()

K

• keys()
• kill()

L

• last()
• lc(string) - returns string in lowercase
• lcfirst(string) - returns string with first character lowercased
• length(string) - returns length (number of characters in) string
• link(oldfile,newfile) - creates newfile as a link to oldfile
• listen(socket,queuesize) - waits for incoming events on a socket
• local(variable list) - makes all variables in variable list local to the current subroutine
• localtime(number) - converts the binary time stored in number to a 9-element list and localizes it to the machine's timezone
• log(number) - returns the natural logarithm (i.e. log_e) of number
• lstat(fileHandle) - returns file statistics for the file opened with file handle fileHandle (does not de-reference symbolic links)

M

• m/pattern/gimosx - performs pattern-matching; other characters may be used as delimiters instead of "/". See Perl regex
• map(expr,list) - returns an array containing the output of expr(list item) for each item in list
• mkdir(name,mode) - creates a directory named name (can be relative or absolute filespec), with the file attributes in mode. See mkdir for related information.
• msgctl
• msgget
• msgrcv
• msgsnd
• my(variable list) - makes all variables in variable list local to the current {block}

N

• next
• no

O

• oct(string) - converts string from octal to decimal
• open(fileHandle, name) - opens a file named name and associates it with fileHandle
• opendir(dirHandle, name) - opens a directory named name and associates it with dirHandle
• ord(string) - returns the ASCII code of the first character in string, as an integer

P

• pack(template, list)
• pipe(readhandle, writehandle)
• pop(array)
• pos(scalar)
• print(filehandle, list)
• printf(filehandle, list)
• push(array, list)

Q

• q/string/
• qq/string/
• quotemeta(string) - prepares a string for use in a regex by backslashing any characters with special meanings
• qw/string/
• qx/string/

R

• rand(number) - returns a random number between 0 and number
• read(filehandle, scalar, length)
• readdir
• readlink
• recv
• redo
• ref
• rename(oldname, newname) - renames file oldname to newname
• require(filename) - executes the Perl code inside file filename (if no path specified, searches Perl path)
• reset
• return
• reverse(list) - reverses the sorting of array list
• rewinddir
• rindex(string, substring) - returns the position of the last occurrence of substring in string
• rmdir