How is this different from Repeating List Item Remover?

Repeating List Item Remover de-duplicates by keeping only the first occurrence of every value, unique or not. Unique List Item Remover instead drops values that occur only once entirely, but keeps every occurrence of values that repeat two or more times, so a value appearing three times still appears three times in the output.

What's the inverse of this tool?

Unique List Item Finder, which keeps exactly the items this tool removes: those appearing exactly once.

What happens if the whole list is unique?

You'll get an error explaining that every item is unique and nothing repeats, since the result would otherwise be an unhelpfully empty output.

Unique List Item Remover - Keep Only Values That Repeat

Overview

Introduction

Sometimes the goal is the opposite of de-duplication: isolating only the values that repeat, discarding every one-off entry entirely.

Unique List Item Remover strips out every exactly-once item, leaving behind only the repeating values, with all of their occurrences intact.

What Is Unique List Item Remover?

A filter that keeps items belonging to any value whose total occurrence count is two or more, and removes items belonging to values that occur exactly once.

Unlike a de-duplication tool, it doesn't collapse repeats down to one copy, every occurrence of a qualifying repeating value survives in the output.

How Unique List Item Remover Works

The input is split into items using the selected separator, then each distinct value's occurrence count is tallied.

Items whose value's count is one are dropped; items whose value's count is two or more are kept, in their original positions and multiplicity.

When To Use Unique List Item Remover

Use it to isolate exactly the values that are duplicated in a dataset, discarding one-off noise entirely.

It's useful before running Repeating List Item Remover, to first confirm which repeating values will survive de-duplication.

Often used alongside Unique List Item Finder, Repeating List Item Remover and Repeating List Item Finder.

Features

Advantages

Keeps every occurrence of a repeating value, not just the first, so counts remain meaningful downstream.
Clear complement to Unique List Item Finder for the opposite half of the same list.

Limitations

Doesn't de-duplicate the repeating values it keeps; run Repeating List Item Remover afterward if you also want one copy of each.
Comparison is exact and case-sensitive with no trimming applied.

Examples

Keeping only repeating values, with all occurrences

Input

apple
banana
apple
cherry
apple

Output

apple
apple
apple

"apple" occurs three times and is fully retained; "banana" and "cherry" each occur once and are removed entirely.

Comma-separated list

Input

a,b,a,c (comma separator)

Output

a, a

Only "a" repeats (twice); "b" and "c" are unique and are dropped.

Best Practices & Notes

Best Practices

Chain with Repeating List Item Remover afterward if you want a de-duplicated list of only the values that originally repeated.
Use Unique List Item Finder first to preview exactly what this tool will remove.

Developer Notes

Builds a `Map<string, number>` frequency table, then filters the original items array keeping only entries where `counts.get(item) >= 2`, which preserves both original order and full multiplicity of repeating values.

Unique List Item Remover Use Cases

Isolating genuinely duplicated entries in a dataset while discarding one-off noise
Preparing a list of "needs review" repeated values before de-duplicating
Auditing which values in a large list actually recur

Common Mistakes

Expecting a de-duplicated result; this tool intentionally keeps every occurrence of each repeating value, not just one.
Confusing this with Repeating List Item Remover, which serves a different purpose (de-duplication, not isolation of repeats).

Tips

If you want a single copy of each repeating value, run Repeating List Item Remover on this tool's output next.
Use a custom separator if your source list isn't newline- or comma-delimited.

Unique List Item Remover