> For the complete documentation index, see [llms.txt](https://docs.veza.com/4yItIzMvkpAvMVFAamTf/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.veza.com/4yItIzMvkpAvMVFAamTf/features/search/regex.md).

# Regular Expressions

Graph search, Query Builder, and Workflows can use regular expressions to filter results with matching attributes.

{% hint style="info" %}
Use regular expressions to create filters with OR conditions, or when complex pattern matching is needed. Otherwise, a built-in operator might already cover your use case (*Contains*, *Starts With*, *Not Ends With*, and others).
{% endhint %}

### Overview

A regular expression is a sequence of characters that define a *pattern* of symbols to match in search results. At the most basic level, a regular expression works similarly to text search: the regular expression `production` will match the exact text string "production". More complex expressions can match a pair of values, such as `dev|production`, or match a sequence of possible characters: `[A-Za-z0-9]`.

### Examples

Using a regular expression when filtering results by attribute can enable flexible searches, workflows, and alert rules. Notably, regular expressions allow for matching more than one combination (*OR*), unlike *contains* and *does not contain* filters (where all conditions must be true).

* Filter by multiple regions: (`us-(east|west)-\d+`)
* Match text containing a string: (`.*production.*`)
* Filter data resources in all US regions: (`us-[A-Za-z]*`)
* Check if a value is an expected format, such as a standard email: `\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b`

#### Notes and Resources

Regular expressions can contain character literals, operators, and constructs. For more information, see:

* [Perl Regular Expressions Tutorial](https://perldoc.perl.org/perlretut)

A variety of sandboxes can be found online for learning, building, and testing regular expressions.

### Supported Expressions

Veza implements a subset of [Perl Compatible Regular Expressions](https://perldoc.perl.org/perlre).

* Special characters such as `*+?()|` must be escaped with `\`

Possible expressions include:

#### Composites

* `xy` - `x` followed by `y`
* `x|y` - `x` or `y` (prefer `x`)

#### Repetitions

* `x*` - zero or more `x`, prefer more
* `x+` - one or more `x`, prefer more
* `x?` - zero or one `x`, prefer one
* `x{n,}` - `n` or more `x`, prefer more
* `x{n}` - exactly `n` `x`
* `x*?` - zero or more `x`, prefer fewer
* `x+?` - one or more `x`, prefer fewer
* `x??` - zero or one `x`, prefer zero
* `x{n,}?` - `n` or more `x`, prefer fewer
* `x{n}?` - exactly `n` `x`

#### Grouping

* `(re)` - numbered capturing group (submatch)
* `(?P<name>re)` - named & numbered capturing group (submatch)
* `(?:re)` - non-capturing group
* `(?flags)` - set flags within current group; non-capturing
* `(?flags:re)` - set flags during re; non-capturing

#### Flags

* `i` case-insensitive (default false)
* `m` multi-line mode (default false)
* `s` let `.` match (default false)
* `U` ungreedy: swap meaning of `x*` and `x*?`, `x+` and `x+?` (default false)

Flag syntax is `xyz` (set) or `-xyz` (clear) or `xy-z` (set `xy`, clear `z`).

#### Empty Strings

* `^` - at beginning of text or line
* `$` - at end of text

#### Character Class Elements

* `.` - any character, possibly including newline.
* `x` - single character
* `A-Z` - character range (inclusive)
* `\d` - Perl character class
* `[:class:]` - ASCII character class `class`
* `\p{class}` - Unicode character class `class`
* `\pF` - Unicode character class `F` (one-letter name
* `[\d]` - digits (≡ `\d`)
* `[^\d]` - not digits (≡ `\D`)
* `[\D]` - not digits (≡ `\D`)
* `[^\D]` - not not digits (≡ `\d`)

#### Perl character classes (ASCII-only)

* `\d` - digits (≡ `[0-9`)
* `\D` - not digits (≡ `[^0-9`)
* `\s` - whitespace (≡ `[\t\n\f`)
* `\S` - not whitespace (≡ `[^\t\n\f`)
* `\w` - word characters (≡ `[0-9A-Za-z_`)
* `\W` - not word characters (≡ `[^0-9A-Za-z_`)

#### ASCII Character Class

* `[[:alnum:]]` - alphanumeric (≡ `[0-9A-Za-z]`)
* `[[:alpha:]]` - alphabetic (≡ `[A-Za-z]`)
* `[[:ascii:]]` - ASCII (≡ `[\x00-\x7F]`)
* `[[:blank:]]` - blank (≡ `[\t ]`)
* `[[:cntrl:]]` - control (≡ `[\x00-\x1F\x7F]`)
* `[[:digit:]]` - digits (≡ `[0-9]`)
* `[[:graph:]]` - graphical (≡ `[!-~]`)
* `[[:lower:]]` - lower case (≡ `[a-z]`)
* `[[:print:]]` - printable (≡ `[ -~]` ≡ `[ [:graph:]]`)
* `[[:punct:]]` - punctuation (≡ `[!-/:-@[-{-~]`)
* `[[:space:]]` - whitespace (≡ `[\t\n\v\f\r ]`)
* `[[:upper:]]` - upper case (≡ `[A-Z]`)
* `[[:word:]]` - word characters (≡ `[0-9A-Za-z_]`)
* `[[:xdigit:]]` - hex digit (≡ `[0-9A-Fa-f]`)


---

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