---
title: "-(_:_:)"
framework: createml
role: symbol
role_heading: Operator
path: "createml/mluntypedcolumn/-(_:_:)-3h4o4"
---

# -(_:_:)

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

## Declaration

```swift
static func - (a: MLUntypedColumn, b: MLUntypedColumn) -> MLUntypedColumn
```

## Parameters

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

## Return Value

Return Value A new column if the columns have the same size and underlying type; otherwise an invalid column.

## See Also

### Combining columns to generate an untyped column

- [+(_:_:)](createml/mluntypedcolumn/+(_:_:)-bcc5.md)
- [*(_:_:)](createml/mluntypedcolumn/*(_:_:)-2p6nm.md)
- [/(_:_:)](createml/mluntypedcolumn/_(_:_:)-45tpp.md)