Overview
Regular expressions (regex) allow you to search for, extract, or replace specific patterns of text in Mailparser.
They can be used in:
- Text filters
- Table filters
Regex is useful when your data follows a consistent format, such as IDs, codes, or numbers.
How It Works
A regular expression defines a pattern that Mailparser looks for in your data.
If the pattern matches, the matching text is returned or modified depending on the filter being used.
Mailparser uses PCRE syntax.
Writing a Regex Pattern
Use Delimiters
All expressions must start and end with a delimiter, typically:
/pattern/
Other delimiters like # can also be used.
Examples
Match a 7 to 9 digit number
/\d{7,9}/Match a code like AB-1234567
/[A-Z]{2}-\d{7}/Common Regex Elements
Character Classes
\d→ digits (0–9)\w→ letters, numbers, underscore\s→ whitespace.→ any character (except newline)
Meta Characters
^→ start of text$→ end of text[]→ character set()→ group|→ OR\→ escape character
Quantifiers
*→ 0 or more+→ 1 or more?→ optional{n}→ exact number{n,m}→ range
These building blocks can be combined to create more precise patterns.
Tips
- Start simple and refine your pattern
- Use
\d,\w, etc. instead of long character sets when possible - Test your regex before applying it
Summary
Regular expressions let you define patterns to find, extract, or modify data in Mailparser. They are powerful for handling structured data, but work best when your input follows a consistent format.