> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/packages/data/csv.md).

# csv

> CSV parsing plus a small dataframe-style toolkit

Use `csv` for CSV parsing, writing, and table-style transforms over arrays of row objects.

```javascript
import "osl/csv"
```

## Example

```javascript
import "osl/csv"

array rows = csv.parse("name,age\nAda,36")
log rows[0]["name"]
```

## API reference

### `csv`

| Method                                                                       | Returns             | Description                            |
| ---------------------------------------------------------------------------- | ------------------- | -------------------------------------- |
| `csv.parse(data: any)`                                                       | `array`             | Parses input data.                     |
| `csv.parseRaw(data: any)`                                                    | `array`             | Parses raw.                            |
| `csv.stringify(data: object)`                                                | `string`            | Serialises a value to text.            |
| `csv.stringifyRows(data: array)`                                             | `string`            | Runs the stringify rows operation.     |
| `csv.stringifyArray(data: array)`                                            | `string`            | Runs the stringify array operation.    |
| `csv.readFile(path: any)`                                                    | `array`             | Reads file.                            |
| `csv.readFileRaw(path: any)`                                                 | `array`             | Reads file raw.                        |
| `csv.writeFile(path: any, data: object)`                                     | `boolean`           | Writes file.                           |
| `csv.writeFileRows(path: any, data: array)`                                  | `boolean`           | Writes file rows.                      |
| `csv.writeFileArray(path: any, data: array)`                                 | `boolean`           | Writes file array.                     |
| `csv.toRows(data: array)`                                                    | `array`             | Converts to rows.                      |
| `csv.fromRows(rows: array)`                                                  | `array`             | Creates from rows.                     |
| `csv.getColumn(data: array, column: any)`                                    | `array`             | Returns column.                        |
| `csv.filter(data: array, fn: any)`                                           | `array`             | Returns values accepted by a callback. |
| `csv.mapRows(data: array, fn: any)`                                          | `array`             | Runs the map rows operation.           |
| `csv.reduce(data: array, initial: any, fn: any)`                             | `any`               | Reduces values with a callback.        |
| `csv.groupBy(data: array, key: any)`                                         | `map[string]array`  | Runs the group by operation.           |
| `csv.sortBy(data: array, key: any)`                                          | `array`             | Runs the sort by operation.            |
| `csv.sortByNum(data: array, key: any)`                                       | `array`             | Runs the sort by num operation.        |
| `csv.aggregate(data: array, key: any, value: any, fn: any)`                  | `object`            | Runs the aggregate operation.          |
| `csv.count(data: array, key: any)`                                           | `object`            | Runs the count operation.              |
| `csv.unique(data: array, key: any)`                                          | `array`             | Runs the unique operation.             |
| `csv.join(data1: array, data2: array, key: any)`                             | `array`             | Runs the join operation.               |
| `csv.pivot(data: array, keyColumn: any, valueColumn: any, pivotColumn: any)` | `map[string]object` | Runs the pivot operation.              |
| `csv.transpose(data: array)`                                                 | `array`             | Runs the transpose operation.          |
| `csv.stats(data: array, key: any)`                                           | `object`            | Returns usage statistics.              |
| `csv.merge(data1: array, data2: array)`                                      | `array`             | Runs the merge operation.              |
| `csv.chunk(data: array, size: any)`                                          | `array`             | Runs the chunk operation.              |
| `csv.flatten(data: array, separator: any)`                                   | `array`             | Runs the flatten operation.            |
| `csv.sample(data: array, count: any)`                                        | `array`             | Runs the sample operation.             |
| `csv.appendRow(data: array, row: object)`                                    | `array`             | Runs the append row operation.         |
| `csv.prependRow(data: array, row: object)`                                   | `array`             | Runs the prepend row operation.        |
| `csv.insertRow(data: array, index: any, row: object)`                        | `array`             | Runs the insert row operation.         |
| `csv.deleteRow(data: array, index: any)`                                     | `array`             | Deletes row.                           |
| `csv.addColumn(data: array, column: any, defaultValue: any)`                 | `array`             | Adds column.                           |
| `csv.removeColumn(data: array, column: any)`                                 | `array`             | Removes column.                        |
| `csv.renameColumn(data: array, oldColumn: any, newColumn: any)`              | `array`             | Runs the rename column operation.      |

## Notes

* Standard-library imports accept both `import "osl/csv"` and `import "csv"`.
* Return values such as `array` and `object` are regular OSL values unless a returned object section says otherwise.