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Prepend a CSV Column

Add a new CSV column at the beginning of every row.

Tool

Use this tool to prepend a new column to CSV data. It is useful when you need to add a fixed field, label, source tag, environment marker, or other leading column before existing CSV data.

About this tool

Use this tool to prepend a new column to CSV data. It is useful when you need to add a fixed field, label, source tag, environment marker, or other leading column before existing CSV data.

Use prepend a csv column when you need a fast browser-based result without extra setup. It works well for quick checks, one-off tasks, and routine formatting or calculation work.

Learn more

Why use this tool

How to use

  1. Put the new column header on the first line
  2. Put one value per CSV row after that
  3. Leave a blank line
  4. Paste the CSV below
  5. Run the tool to add the new first column

Examples

Example

Input

source
api
api

name,role
John,admin
Anna,editor

Output

source,name,role
api,John,admin
api,Anna,editor

Useful when you want every row labeled with its source.

Example

Input

env
prod
prod

id,title
1,Book
2,Pen

Output

env,id,title
prod,1,Book
prod,2,Pen

Adds a new leading field before the existing CSV columns.

Common errors

The number of new values does not match the number of CSV data rows

Fix: Provide one new value for each CSV row below the header.

Forgetting the blank line before the CSV body

Fix: Put the new header and values first, then a blank line, then the CSV.

Using broken CSV input

Fix: Make sure the CSV itself is valid before adding a new column.

FAQ

What does Prepend a CSV Column do?

It adds a new column at the beginning of the CSV and fills it with your provided values.

Do I need one value per row?

Yes. You should provide one value for each CSV data row.

Does it change the existing columns?

No. It only adds a new first column and keeps the others in place.

What if my values count does not match the row count?

The tool returns an error so you can fix the input.

How is it different from Append a CSV Column?

Prepend adds the new column first, while Append adds it at the end.

Use cases

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