Duplicate headers
What they are and how to fix them
What are duplicate headers?
Duplicate headers mean two or more columns share the same name. That makes transformations ambiguous and can silently overwrite values in tools that expect unique field names. RxLint surfaces duplicates so you can rename them safely.
Example data with this issue
| id | ||
|---|---|---|
| 1 | alice@example.com | a@example.com |
| 2 | bob@example.com | b@example.com |
Frequently asked questions
How do duplicate headers cause data loss?
Some tools keep only one value for a repeated key. When headers are duplicated, one column can overwrite another during parsing or mapping.
How should I rename duplicates?
Use explicit names that represent meaning, such as primary_email and backup_email, instead of numbering columns without context.