f
by()
Calculate the mean value for each column in the frame.
Frame
The frame will have one row and the same number/names of columns as in the current frame. All columns will have float64 stype. For string/object columns this function returns NA values.
float64
.mean1() – similar to this method, but operates on a single-column frame only, and returns a scalar value instead of a Frame.
.mean1()
dt.mean() – function for counting mean values in a column or an expression; can also be applied per-group.
dt.mean()