Remove Duplicates
Free online tool to remove duplicate lines from text. Options for case sensitivity, trim whitespace, and preserve original order. Instant results.
Why Use Our Remove Duplicates Tool?
Our duplicate line remover helps you clean up text by removing repeated lines while giving you control over how duplicates are detected. Whether you're cleaning a mailing list, deduplicating data entries, or organizing a list, the tool provides flexible options for case sensitivity, whitespace handling, and order preservation.
Key Features
- Remove duplicate lines while preserving unique entries
- Case sensitivity toggle for precise matching
- Trim whitespace option to catch duplicates with extra spaces
- Preserve order toggle to maintain original sequence
- Live statistics showing duplicates found and removed
How to Use This Tool
- Paste or type your text with duplicate lines
- Configure options: case sensitivity, trim whitespace, preserve order
- Results appear automatically as you adjust settings
- Copy the cleaned text or reset to start over
Technical Details
The duplicate remover uses a Set-based algorithm for O(n) deduplication. When case-insensitive mode is enabled, lines are normalized to lowercase before comparison while preserving the original case in output. Whitespace trimming uses String.trim() before comparison. Order preservation maintains first-occurrence ordering using an insertion-tracking Set.
Frequently Asked Questions
Does it remove all occurrences of a duplicate?
It keeps one instance of each unique line and removes all subsequent duplicates. The first occurrence is always preserved.
What does 'Preserve Order' do?
When enabled, unique lines appear in the same order as their first occurrence in the original text. When disabled, the order may differ.
How does case sensitivity work?
When case-sensitive, 'Hello' and 'hello' are treated as different lines. When case-insensitive, they're considered duplicates and only the first occurrence is kept.
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