A data.frame with the selected columns and column "g".
Arguments
.c
A chronicle object.
columns
Columns to select for the output. Defaults to c("ops_number", "function").
Details
`.g` is an option argument to the `record()` function. Providing this optional
function allows you, at each step of a pipeline, to monitor interesting characteristics
of the `value` object. See the package's Readme file for an example with data frames.