Grammar Regular Expression Engine

Updated 1 year ago by admin

This section describes the regular expressions syntax that the Advanced DLP add-on supports.

The DLP engine parser interprets regular expression syntax nearly identically to the UNIX regular expression syntax.

Operators

The following table describes the base regular expression operators available in the DLP engine, and the pattern the operator matches.

Operator

Matched Pattern

\

Quote the next metacharacter

^

Match the beginning of a line

$

Match the end of a line

.

Match any character (except newline)

|

Alternation

()

Used for grouping to force operator precedence

[xy]

The character x or y

[x-y]

The range of characters between x and z

[^z]

Any character except z

For performance reasons, it is recommended that you explicitly list all the characters that you want to match, rather than using this operator
To use negated character classes in case-insensitive entities, you must include letters in both cases, for example [^Zz] rather than [^z]

Quantifiers

Operator

Matched Pattern

*

Match 0 or more times

+

Match 1 or more times

?

Match 0 or 1 times

{n}

Match exactly n times

{n,1}

Match at least n times

{n,m}

Match at least n times, but no more than m times

Metacharacters

Operator

Matched Pattern

\t

Match tab

\n

Match newline

\r

Match return

\f

Match formfeed

\a

Match alarm (bell, beep, and so on)

\e

Match escape

\v

Match vertical tab

\021

Match octal character (in this example, 21 octal)

\xF0

Match hex character (in this example, F0 hex)

\x{263a}

Match wide hex character (Unicode)

\w

Match word character: [A-Za-z0-9_]

\W

Match non-word character: [^A-Za-z0-9_]

\s

Match whitespace character. This metacharacter also includes \n and \r: [ \t\n\r]

\S

Match non-whitespace character: [^ \t\n\r]

\d

Match digit character: [0-9]

\D

Match non-digit character: [^0-9]

\b

Match word boundary

\B

Match non-word boundary

\A

Match start of string (never match at line breaks)

\Z

Match end of string. Never match at line breaks; only match at the end of the final buffer of text submitted for matching

\p{class}

Match any character that belongs to the specified Unicode character class. For example, \p{Sc} matches any currency symbol. You can omit the braces for single-character class names: \p{C} and \pC are equivalent

\P{class}

Match any character that does not belong to the specified Unicode character class. For example \P{Sc} matches any character that is not a currency symbol. You can omit the braces for single-character class names: \P{C} and \PC are equivalent

For performance reasons, it is recommended that you avoid using negated character classes where possible

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