CSV transpose

csv-transpose · version 1.0.0 · CSV & tables · free, no key needed

Transpose a CSV matrix including the header row, then re-validate headers.

Use when you need to: csv transpose · transpose csv · csv rotate columns to rows.

Supported

• csv transpose
• transpose csv
• csv rotate columns to rows

Not supported

• jagged fill
• multi-header
• read files

Behavior

• Reuse baseline parser: the document is a rectangular matrix of header plus data rows.
• Transpose that full matrix (header row is row 0).
• The first row of the transposed matrix becomes the new header and must pass unique/non-empty/byte/column limits.
• Empty document -> csv "".
• Header-only (one row, N columns) becomes N rows and 1 column whose header is the original first header name, data the remaining original headers.
• Reject if transpose would exceed max_columns or max_data_rows.

Input

• csv (string, required): max length 256000

Output

• csv (string, required)
• rows_in (integer, required)
• cols_in (integer, required)
• rows_out (integer, required)
• cols_out (integer, required)

Limits

• max input bytes: 256000
• max data rows: 5000
• max columns: 256
• max header name bytes: 256

Example

Request input:

{
  "csv": "h1,h2\na,b\nc,d\n"
}

Response:

{
  "result": {
    "csv": "h1,a,c\nh2,b,d\n",
    "rows_in": 2,
    "cols_in": 2,
    "rows_out": 1,
    "cols_out": 3
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "csv-transpose",
  "version": "1.0.0",
  "input": {
    "csv": "h1,h2\na,b\nc,d\n"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/csv-transpose/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"csv":"h1,h2\na,b\nc,d\n"}'

The machine-readable contract is at /v1/tools/csv-transpose/versions/1.0.0.

CLI

node cli.mjs run csv-transpose 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• CSV dedupe: Remove duplicate CSV data rows while preserving the first occurrence.
• CSV group count: Count CSV rows by exact named-column tuples in first-seen order.
• CSV sort: Stably sort CSV rows by exact named string columns.
• CSV to JSON: Convert a complete CSV document into an array of string-valued objects.
• CSV add row number: Prepend a 1-based row_number column of canonical integer strings.
• CSV anti join: Keep left CSV rows whose exact key tuples do not appear in the right document.