---
title: "-(_:_:)"
framework: createml
role: symbol
role_heading: Operator
path: "createml/mldatacolumn/-(_:_:)-3mwsr"
---

# -(_:_:)

Creates a column of doubles by subtracting each element in the second column from the corresponding element in the first column.

## Declaration

```swift
static func - (a: MLDataColumn<Double>, b: MLDataColumn<Double>) -> MLDataColumn<Double>
```

## Parameters

- `a`: A column of doubles.
- `b`: A column of doubles.

## Return Value

Return Value A new column of doubles if the columns are the same size; otherwise an invalid column.

## See Also

### Combining columns to generate a column

- [+(_:_:)](createml/mldatacolumn/+(_:_:)-24g38.md)
- [+(_:_:)](createml/mldatacolumn/+(_:_:)-q5bb.md)
- [-(_:_:)](createml/mldatacolumn/-(_:_:)-11hbf.md)
- [*(_:_:)](createml/mldatacolumn/*(_:_:)-40smy.md)
- [*(_:_:)](createml/mldatacolumn/*(_:_:)-lchb.md)
- [/(_:_:)](createml/mldatacolumn/_(_:_:)-5uxby.md)
- [/(_:_:)](createml/mldatacolumn/_(_:_:)-69vgc.md)