rechunk: Increase or decrease the number of chunks in the disk.frame

In xiaodaigh/disk.frame: Larger-than-RAM Disk-Based Data Manipulation Framework

Increase or decrease the number of chunks in the disk.frame

Description

Increase or decrease the number of chunks in the disk.frame

Usage

rechunk(
  df,
  nchunks = disk.frame::nchunks(df),
  outdir = attr(df, "path", exact = TRUE),
  shardby = NULL,
  overwrite = TRUE
)

Arguments

df	the disk.frame to rechunk
nchunks	number of chunks
outdir	the output directory
shardby	the shardkeys
overwrite	overwrite the output directory

Examples

# create a disk.frame with 2 chunks in tempdir()
cars.df = as.disk.frame(cars, nchunks = 2)

# re-chunking cars.df to 3 chunks, done "in-place" to the same folder as cars.df
rechunk(cars.df, 3)

new_path = tempfile(fileext = ".df")
# re-chunking cars.df to 4 chunks, shard by speed, and done "out-of-place" to a new directory
cars2.df = rechunk(cars.df, 4, outdir=new_path, shardby = "speed")

# clean up cars.df
delete(cars.df)
delete(cars2.df)

xiaodaigh/disk.frame documentation built on Feb. 3, 2023, 10:04 p.m.