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CSV Column Joiner
Join selected columns within each CSV record using a literal separator, while retaining every original field and row.
UTF-8 CSV or TSV file, Pasted delimited text
Quoted delimited CSV
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Paste CSV input or choose a CSV file; the file takes precedence. Select Input delimiter.
- Enter Ordered column numbers, Literal separator (empty is allowed) and New column name. Choose Protect spreadsheet formulas as required.
- Select Join columns, then Download result for joined-columns.csv. Edit input clears prior output; Cancel stops the worker and Reset restores defaults.
Examples
Selecting columns 3,2 from the record [001, first, last], with separator |, appends last|first and retains every original field.
Limitations
- 5 MiB input,50000 data rows,500 output columns,500000 output cells including header,100 UTF-16 separator units,20 MiB output and 30 seconds.
- Headers must be nonempty/unique and remain unique after selected protection. Expanded output is conservatively checked before joining, reserving a possible protection byte per field.
- Default-on protection applies once to untrusted originals, new header and joined field. Complete signed decimal/exponent spellings remain literal. CSV does not declare spreadsheet cell types.
- No templates, expressions, trimming, skipped empty fields or relational joins.
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