Remove CSV duplicates by column

Instructions

1. Drop a .csv file. Remove duplicates by column is already selected.
2. Check one or more columns. Preview does not remove rows until you do.
3. Read the rows that would be dropped, then apply.
4. Download the remaining table. The kept row still has its original cell text.

Example

Select the name column. The city column is different on the second row, and the third name is not the same case.

name,city
Ada,Tokyo
Ada,Osaka
ada,Tokyo

Ada,Osaka is removed. ada,Tokyo stays because the lowercase name is a different key. The kept Ada row still reads Ada,Tokyo.

How the comparison key is built

Each selected cell is trimmed for the comparison only. The row you keep is not rewritten, so a kept name can still have spaces around it. Letter case still matters: Ada and ada are different keys.

Columns you leave unchecked are ignored. Ada,Tokyo and Ada,Osaka become one row when only the name column is selected. The Osaka row is removed, not merged.

Columns are chosen by position

The checkbox shows the header and the column number. If two headers share a name, you can still pick one of them, because the cleaner addresses columns by position.

An empty cell and a cell that contains only spaces match each other. They do not match a cell with any other character.

Limitations

• With no column selected, preview explains that and does not delete rows.
• Trimming applies to the comparison only. This page does not trim the cells you keep.
• The first row wins. A later row is discarded, and its other columns are not copied onto the kept row.
• Selecting every column is still not an exact duplicate check, because these keys are trimmed and exact duplicates are not.
• CSV and .xlsx up to 32 MB. The download is CSV. Save .xls as .xlsx first.