datatable.FExpr.__bool__()

datatable.FExpr.

__bool__

(

)

source

Using this operator will result in a TypeError.

The boolean-cast operator is used by Python whenever it wants to know whether the object is equivalent to a single True or False value. This is not applicable for a FExpr, which represents stored computation on a column or multiple columns. As such, an error is raised.

In order to convert a column into the boolean stype, you can use the type-cast operator dt.bool8(x).