Remove Duplicate Words
Remove Duplicate Words extracts word-like letter/number/apostrophe/hyphen runs, lowercases each only for the Seen key, keeps the first original-cased spelling, and joins survivors with single spaces. All original punctuation, emoji, line breaks, and spacing are discarded. It removes repeats globally, not merely adjacent duplicates, and performs no stemming, Unicode normalization, or language-aware equivalence.
Runs locally — files stay on your deviceAre only adjacent duplicate words removed?
No. Later repeats anywhere are removed.
Global token deduplication is intentionally lossy
After separators are discarded, keeping one surface token cannot preserve the source sentence grammar or layout.
How it works
The shared regex extracts tokens; a lowercase Set filters later repeats; single spaces join survivors.
Key concepts
First casing wins
Word word becomes Word.
All separators lost
Only selected tokens survive.
When to use it
- Create a unique-token list retaining first casing.
- Inspect vocabulary order of first appearance.
- Remove repeats from a plain bag-of-words input.
When not to use it
- Do not use on prose expecting grammar preserved.
- Do not expect punctuation or lines retained.
- Do not expect stemming or semantic dedupe.
Worked examples
Global
- Input
one two one- Expected output
one two
Later one removed.
Case
- Input
Cat cat CAT- Expected output
Cat
Lowercase comparison.
Punctuation
- Input
hello, world!- Expected output
hello world
Punctuation disappears.
Common mistakes
Using on prose
Repeated function words are meaningful. Correction: Use only for token lists.
Expecting adjacent-only
Set is global. Correction: Use a consecutive-repeat tool.
Assuming semantic grouping
Forms remain separate. Correction: Use NLP.
Best practices
- Treat output as a token list.
- Keep source.
- Document global case-insensitive behavior.
Related operations and differences
Remove Duplicate Lines
Choose Remove Duplicate Lines when you need to keep only the first occurrence of every line.; use Remove Duplicate Words specifically for remove duplicate words.
Unique Word Counter
Choose Unique Word Counter when you need to count distinct words without case differences.; use Remove Duplicate Words specifically for remove duplicate words.
Add Prefix to Every Line
Choose Add Prefix to Every Line when you need to add the same prefix before every line.; use Remove Duplicate Words specifically for remove duplicate words.
Add Suffix to Every Line
Choose Add Suffix to Every Line when you need to add the same suffix after every line.; use Remove Duplicate Words specifically for remove duplicate words.
Capitalize Every Word
Choose Capitalize Every Word when you need to capitalize the first character of every word.; use Remove Duplicate Words specifically for remove duplicate words.
Character Counter
Choose Character Counter when you need to count Unicode characters in text.; use Remove Duplicate Words specifically for remove duplicate words.
Limitations and privacy
- Regex token extraction, global basic-lowercase Set, single-space join; no punctuation/format preservation, adjacent mode, normalization, stemming, lemmatization, locale folding, counts, or removal report.
The text is analyzed locally in this browser and is not uploaded by the tool.
Frequently asked questions
Is matching case-insensitive?
Through basic lowercasing, yes.
Is first spelling preserved?
Yes.
Is punctuation kept?
No.
Are repeats removed globally?
Yes.