Any Reliable Solution to Remove Duplicate From Large CSV File?

Shubham Singh

I’m working with a large CSV file and facing issues with duplicate entries. I need a reliable way to remove duplicates without losing any important data or messing up the file structure.

I’ve tried a few basic methods, but they either don’t work well with large files or risk data loss. I’m looking for a safe and efficient solution.

Someone suggested the SysTools CSV Duplicate Remover Tool, saying it can handle large files and remove duplicates accurately. Has anyone here used it? Is it reliable, or are there better alternatives?

Any suggestions would be really helpful.

3 Replies

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the real gabrus4mo ago
Accepted answer
There are many manual methods which you can use but if in your case manual solution didn't work then you can use reliable and professional solutions like SysTools CSV Duplicate Remover Tool to remove and clean your large CSV data files.
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Parag Banerjee4mo ago
I’ve faced this issue before, and the key is how you define “duplicate.” For exact duplicates, you don’t really need a paid tool.
For large CSVs, Python (pandas) is a reliable option—you can remove duplicates safely and control what gets kept. If you prefer no-code, try Excel Power Query or OpenRefine.
I haven’t used SysTools personally, but it should work for basic cases. Just take a backup and test on a small sample first.
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Sam Hobbs4mo ago
First define what are duplicates. The answer is not as easy as you assume.
I assume that you mean there is a specific field, such as a person's name, for which there might be multiple occurrences of the same value in the name column. Is it only one specific field?
What happens when other columns have values that are different?
Another criteria is whether the file can all fit it in memory.
You can use the `SortedList.Add(TKey, TValue)` class or similar collection. For each new record, check if the key exists. If not then add the record. If it does exist then you could check other fields if relevant. I wrote something like that in 1973 using COBOL without the convenience that .Net provides.
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