Notepad find and replace with regex capture groups
Jul 28, 2025 am 02:17 AMUse regular expression capture group in Notepad to effectively reorganize text. First, you need to open the replacement dialog box (Ctrl H), select "Search Mode" as "regular expression", 1. Use () to define the capture group, such as (\w ) to capture words; 2. Use \1 and \2 to reference the corresponding group in the replacement box; 3. Example: Exchange the name "John Doe" as "Doe, John", find (\w )\s (\w ), replace it with \2, \1; 4. Date format conversion 2023-12-25 to 25/12/2023, find (\d{4})-(\d{2})-(\d{2}), replace it with \3/\2/\1; 5. Log reordering can extract time, level, ID and other information and reconstruct it; note Notepad Using the Boost engine, only numbered groups are supported, not named groups, and can use $1 or \1 references. Use small samples to verify first during testing, and optimize performance in combination with non-capture groups (?:...). This function is suitable for fast text reconstruction and data cleaning.
In Notepad , you can use regular expressions (regex) with capture groups in the Find and Replace feature to dynamically restructure or reformat text. This is especially useful for log parsing, code refactoring, or data cleanup.

Here's how to use regex capture groups effectively in Notepad :
? How to Enable Regex Mode
- Open the Find and Replace dialog (
Ctrl H
) - At the bottom, select "Search Mode" → "Regular expression"
- Make sure ". matches newline" is unchecked unless you need multiline matching
? Understanding Capture Groups
Capture groups are defined using parentsheses ()
in regex.
You can then refer to them in the Replace field using \1
, \2
, etc., where:

-
\1
= first captured group -
\2
= second captured group - and so on
? Example 1: Swapping First and Last Names
Suppose you have:
John Doe Jane Smith
You want to convert it to:

Doe, John Smith, Jane
Find what:
(\w )\s (\w )
Replace with:
\twenty one
? Explanation:
(\w )
captures first name (group 1)\s
matches one or more spaces(\w )
captures last name (group 2)\2, \1
reverses the order
? Example 2: Reformatting Dates
Change 2023-12-25
to 25/12/2023
Find what:
(\d{4})-(\d{2})-(\d{2})
Replace with:
\3/\2/\1
? Groups:
\1
= year\2
= month\3
= day
? Example 3: Extracting and Reformatting Log Entries
Original:
[ERROR] User login failed for user_id=12345 at 2023-01-01 [WARN] Timeout on request from IP=192.168.1.1
You want:
2023-01-01: ERROR - user_id 12345 192.168.1.1: WARN - Timeout
You may need multiple steps, but here's a partial example:
Find what:
\[(\w )\].*?user_id=(\d ).*?at (\d{4}-\d{2}-\d{2})
Replace with:
\3: \1 - user_id \2
?? Important Notes
- Notepad uses the Boost regex engine , which supports basic capture groups but has some limitations.
- No named groups like
(?<name>...)</name>
— only numbered groups\1
,\2
, etc. - Backreferences in Find work too : You can use
\1
in the "Find what" field to match repeated text.- Example: Find duplicated words:
(\b\w \b)\s \1
→ matches "the"
- Example: Find duplicated words:
- Escaping : Use
$$
if you need a literal$
in replace (though$1
,$2
also work instead of\1
,\2
in Notepad )
? Pro Tips
- Test on a small sample first
- Use "Find Next" to verify your regex matches correctly
- Use
\K
to keep text before (advanced, not always reliable in older versions) - Use non-capturing groups
(?:...)
if you need grouping without capturing
Summary
Using regex capture groups in Notepad lets you:
- Rearrange text dynamically
- Extract and reformat structured data
- Clean logs, CSVs, or code quickly
Just remember:
- Enable Regular expression mode
- Use
()
to capture - Use
\1
,\2
, etc., in the replace field
It's not as powerful as full scripting, but for quick text surgery, it's incredibly effective.
Basically, if it's structured, you can reshape it.
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