Perl built-in functions

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Computing: Programming: Perl: built-in functions

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By Type

Arrays

  • join(demarc,array) – 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. loge) 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

S