strip_splits: Remove splitting variables from a data frame.
Description
Remove splitting variables from a data frame.
Usage
strip_splits(df)
Arguments
df
data frame produced by d*ply.
Details
This is useful when you want to perform some operation to
every column in the data frame, except the variables that
you have used to split it. These variables will be
automatically added back on to the result when combining
all results together.