What this tool actually changes
Duplicate list items by copies and method.
This kind of tool is most helpful when manual editing would be slower, more error-prone, or too opaque to verify quickly.
How settings shape the output
Duplicate List produces new output from rules, parameters, or patterns instead of editing an existing document. That makes input settings more important than input text, because the settings are what define the shape of the result.
List tools usually treat each line or separator-delimited value as a discrete item, so separators and blanks affect the result.
This tool is deterministic: the same input and the same settings produce the same output every time. All processing happens in your browser, so your input stays on your device during the transformation.
Where this tool earns its keep
Create repeated datasets.
Expand lists for testing.
Duplicate lists with custom separators.
Examples
Quick before and after
Input
Duplicate List input:
Email: john.doe@example.com
Status: active
Output
Duplicate List output:
Email: john.doe@example.com
Status: active
Settings drive the output
Input
Start: 1
Count: 3
Output
1
2
3
Input expectations and common surprises
Generators are only as useful as the settings behind them. When the output seems off, check the count, range, delimiter, seed values, or pattern options before judging the result itself.
For deterministic tools, the same input and the same settings should reproduce the same result. If not, the input likely changed in a small but meaningful way.