# CSV filter empty

`csv-filter-empty` · version 1.0.0 · CSV & tables · free, no key needed

Keep or drop CSV rows whose named column is the empty string.

**Use when you need to: csv filter empty · drop empty csv cells · keep empty csv cells.**

## Supported

- csv filter empty
- drop empty csv cells
- keep empty csv cells

## Not supported

- whitespace as empty
- null inference
- read files

## Behavior

- Reuse baseline CSV parser/stringifier and limits.
- column is an exact header name.
- A cell is empty iff it is the empty string after parse (quoted empty counts as empty).
- keep_empty true: keep only rows where the cell is empty. false (default): keep only rows where the cell is non-empty.
- Whitespace-only cells are not empty. Stable row order.

## Input

- `csv` (string, required): max length 256000
- `column` (string, required): min length 1; max length 256
- `keep_empty` (boolean, optional)

## Output

- `csv` (string, required)
- `rows_in` (integer, required)
- `rows_out` (integer, required)

## Limits

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

## Example

Request input:

```json
{
  "csv": "k,v\na,1\nb,\n",
  "column": "v"
}
```

Response:

```json
{
  "result": {
    "csv": "k,v\na,1\n",
    "rows_in": 2,
    "rows_out": 1
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "csv-filter-empty",
  "version": "1.0.0",
  "input": {
    "csv": "k,v\na,1\nb,\n",
    "column": "v"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/csv-filter-empty/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"csv":"k,v\na,1\nb,\n","column":"v"}'
```

The machine-readable contract is at [/v1/tools/csv-filter-empty/versions/1.0.0](/v1/tools/csv-filter-empty/versions/1.0.0).

### CLI

```sh
node cli.mjs run csv-filter-empty 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [CSV fill defaults](/tools/csv-fill-defaults): Replace empty cells in named CSV columns with exact default strings.
- [CSV anti join](/tools/csv-anti-join): Keep left CSV rows whose exact key tuples do not appear in the right document.
- [CSV drop columns](/tools/csv-drop-columns): Drop named CSV columns and keep the remaining columns in original header order.
- [CSV filter equals](/tools/csv-filter-equals): Keep CSV data rows whose named column equals an exact string.
- [CSV replace exact](/tools/csv-replace-exact): Replace CSV data cells whose entire value equals an exact find string.
- [CSV abs integer column](/tools/csv-abs-integer-column): Replace every data cell in a named CSV column with the absolute value of a canonical integer.