Duplicate Line Remover
Clean up text lists by removing repeated and duplicate lines while preserving original order or sorting alphabetically.
What is Duplicate Line Remover?
Our Duplicate Line Remover cleans lists and datasets by eliminating repeated lines using high-speed in-memory hash set deduplication (O(N) time complexity). Choose whether to preserve original list order, sort lines alphabetically (A–Z or Z–A), trim whitespace, or ignore letter casing with complete local privacy.
Designed for accuracy, speed, and privacy, this tool runs entirely on your local device with zero network latency.
How to Use the Duplicate Line Remover
- 1Paste your list of URLs, email addresses, keywords, or data records into the input editor.
- 2Configure deduplication toggles: "Case Sensitive", "Trim Whitespace", and "Remove Empty Lines".
- 3Select your output order: "Preserve Original Order", "Sort A–Z", or "Sort Z–A".
- 4Review the count of duplicate lines removed and click "Copy Result" or "Download .txt".
Formula & Calculation Logic
Normalizes each line based on active trim and case-folding settings, filtering subsequent duplicates in a single linear pass using a JavaScript Set hash lookup to ensure maximum speed on large datasets.
Deduplication: UniqueLines = Array.from(new Set(lines.map(line => normalize(line)))) | Complexity: O(N)Duplicate Line Remover Frequently Asked Questions
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