Perl Regular Expression Quick Reference Card printable pdf download

Perl Regular Expression Quick Reference Card

Syntax

[0-9]

A digit

[ˆ0-9]

Revision 0.1 (draft) for Perl 5.8.5

A nondigit

Escapes the character immediately following it

[a-zA-Z0-9 ]

Iain Truskett (formatting by Andrew Ford)

A word character

Matches any single character except a newline (un-

[ˆa-zA-Z0-9 ]

A non-word character

less /s is used)

[ \t\n\r\f]

A whitespace character

Matches at the beginning of the string (or line, if /m

[ˆ \t\n\r\f]

A non-whitespace character

is used)

Matches at the end of the string (or line, if /m is used)

Match a byte (with Unicode, ‘.’ matches a charac-

Matches the preceding element 0 or more times

ter)

Matches the preceding element 1 or more times

\pP

Match P-named (Unicode) property

Matches the preceding element 0 or 1 times

\p{...}

Match Unicode property with long name

{...}

Speciﬁes a range of occurrences for the element pre-

\PP

Match non-P

ceding it

\P{...}

Match lack of Unicode property with long name

[...]

Matches any one of the characters contained within

Match extended unicode sequence

This is a quick reference to Perl’s regular expressions. For full

the brackets

information see the perlre and perlop manual pages.

(...)

Groups subexpressions for capturing to $1, $2...

POSIX character classes and their Unicode and Perl equivalents:

(?:...)

Groups subexpressions without capturing (cluster)

Matches either the subexpression preceding or fol-

alnum

IsAlnum

lowing it

alpha

IsAlpha

\1, \2 ...

The text from the Nth group

ascii

IsASCII

Operators

blank

IsSpace

Escape sequences

cntrl

IsCntrl

digit

IsDigit

These work as in normal strings.

graph

IsGraph

=˜ determines to which variable the regex is applied. In its ab-

Alarm (beep)

lower

IsLower

sence, $_ is used.

IsPrint

Escape

$var =˜ /foo/;

punct

IsPunct

Formfeed

!˜ determines to which variable the regex is applied, and negates

space

IsSpace

Newline

the result of the match; it returns false if the match succeeds,

IsSpacePerl

Carriage return

and true if it fails.

upper

IsUpper

Tab

$var !˜ /foo/;

word

IsWord

\038

Any octal ASCII value

m/pattern/igmsoxc

xdigit

IsXDigit

\x7f

Any hexadecimal ASCII value

searches a string for a pattern match, applying the given op-

\x{263a}

A wide hexadecimal value

tions.

case-insensitive

\cx

Control-x

Within a character class:

global – all occurrences

\N{name}

A named character

multiline mode – ˆ and $ match internal lines

Lowercase next character

match as a single line – . matches \n

POSIX

traditional

Unicode

Titlecase next character

compile pattern once

[:digit:]

\p{IsDigit}

Lowercase until \E

extended legibility – free whitespace and com-

[:ˆdigit:]

\P{IsDigit}

Uppercase until \E

ments

Disable pattern metacharacters until \E

don’t reset pos on failed matches when using /g

End case modiﬁcation

If pattern is an empty string, the last successfully matched

This one works differently from normal strings:

regex is used. Delimiters other than ‘/’ may be used for both

Anchors

An assertion, not backspace, except in a character

this operator and the following ones.

class

qr/pattern/imsox

All are zero-width assertions.

lets you store a regex in a variable, or pass one around. Mod-

iﬁers as for m// and are stored within the regex.

Character classes

Match string start (or line, if /m is used)

s/pattern/replacement/igmsoxe

Match string end (or line, if /m is used) or before

substitutes matches of pattern with replacement. Modiﬁers

[amy]

Match ‘a’, ‘m’ or ‘y’

newline

as for m// with one addition:

[f-j]

Dash speciﬁes range

Match word boundary (between \w and \W)

evaluate replacement as an expression

[f-j-]

Dash escaped or at start or end means ‘dash’

Match except at word boundary (between \w and \w

‘e’ may be speciﬁed multiple times. replacement is inter-

[ˆf-j]

Caret indicates “match any character except these”

or \W and \W)

preted as a double quoted string unless a single-quote (’) is

The following sequences work within or without a character class.

Match string start (regardless of /m)

the delimiter.

The ﬁrst six are locale aware, all are Unicode aware. The default

?pattern?

Match string end (before optional newline)

character class equivalent are given. See the perllocale and perlu-

is like m/pattern/ but matches only once. No alternate de-

Match absolute string end

nicode man pages for details.

limiters can be used. Must be reset with reset.

Match where previous m//g left off

Perl Regular Expression Quick Reference Card

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