# datatable.FExpr.extend()¶

Append FExpr arg to the current FExpr.

Each FExpr represents a collection of columns, or a columnset. This method takes two such columnsets and combines them into a single one, similar to cbind().

## Parameters¶

arg
FExpr

The expression to append.

return
FExpr

New FExpr which is a combination of the current FExpr and arg.