---
title: prototype
framework: tabulardata
role: symbol
role_heading: Instance Property
path: tabulardata/anycolumn/prototype
---

# prototype

A prototype that creates type-erased columns with the same underlying type as the column slice.

## Declaration

```swift
var prototype: any AnyColumnPrototype { get }
```

## Discussion

Discussion Use a type-erased column prototype to create new columns of the same type as the slice’s parent column without explicitly knowing what type it is, by calling the prototype property’s makeColumn(capacity:) method. // Get a type-erased column. let someColumn: AnyColumn = dataFrame["someFeature"]

// Create a new column with the same type. let newColumn = someColumn.prototype.makeColumn(capacity: 10)