disk.frame (version 0.5.0)

srckeep: Keep only the variables from the input listed in selections

Description

Keep only the variables from the input listed in selections

Usage

srckeep(diskf, selections, ...)
srckeepchunks(diskf, chunks, ...)

Arguments

diskf

a disk.frame

selections

The list of variables to keep from the input source

...

not yet used

chunks

The chunks to load

Examples

# NOT RUN {
cars.df = as.disk.frame(cars)

# when loading cars's chunks into RAM, load only the column speed
collect(srckeep(cars.df, "speed"))

# clean up cars.df
delete(cars.df)
# }