List Filter
Keep or remove lines matching a plain-text substring or regular expression. Useful for filtering log output, cleaning data, or extracting matching lines from large lists.
How to use the list filter
Type a substring (or regex pattern). Choose to keep matching lines or drop them. Case sensitivity is configurable.
Formula & explanation
Plain mode does a case-insensitive substring match by default; regex mode uses your pattern as JavaScript regex.
Examples
Pattern "a", keep mode → only lines containing "a". Switch to drop mode to remove them.
Frequently asked questions
- How do I remove lines that contain a specific word?
- Type the word in the Pattern field and select Drop mode. Every line containing that word will be removed from the output.
- Can I filter using regular expressions?
- Yes — enable the Regex toggle and enter any JavaScript regular expression, such as ^error to match lines starting with 'error'.
- Is the filter case-sensitive?
- No by default. Enable 'Case sensitive' if you need exact case matching, for example to distinguish 'NULL' from 'null'.
- What is a common use case for list filtering?
- Cleaning log files by removing noise lines, extracting only error lines from a large output, or filtering a CSV export by a keyword.
Related list tools tools
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- List Set OperationsPerform set operations on two lists: union, intersection, difference, A-only, B-only, and symmetric difference. Paste two lists and choose the operation — results update instantly.
- Comma to Lines ConverterConvert between comma-separated values and one-item-per-line format. Handles quoted fields, trims whitespace, and removes duplicates. Paste CSV data, get a clean list — and back.
- List to JSON ArrayConvert a one-item-per-line list into a JSON array of strings and back again. Handles quoting and escaping automatically — useful for turning clipboard lists into API payloads.
- Prefix / Suffix WrapperWrap every line with a custom prefix and suffix. Useful for building SQL IN clauses ('value'), quoting shell arguments, wrapping HTML tags, or generating code from a list.
- Number Sequence GeneratorExpand range patterns like 1..100 or 0,2,4..20 into complete numeric lists. Supports step size, comma-separated output, and custom separators — great for test data and scripting.