Using R's {data.table}'s excellent `fread` in Julia
Author xiaodaigh
1 Star
Updated Last
1 Year Ago
Started In
October 2019

Introduction - Fread.jl

Convert CSVs to feather or parquet

You can use this package to convert CSVs to feather and parquet files

using Fread

csv_to_feather(path_to_csv, outpath)
csv_to_parquet(path_to_csv, outpath)


using Pkg

Install R packages

You need to make sure you have {data.table} and {feather} installed in your R. E.g. in your R session

install.packages(c("data.table", "feather"))


Use CSV.jl instead

You should really be using CSV.jl because it performs quite well. I only use Fread.jl for converting data from parquet to feature etc now and not for reading CSVs as CSV.jl is actually really good.


To use the default parameters of fread

using Fread

a = fread(path_to_csv)

To use customised parameters/arguments, you must set them by name using arg = e.g.

using Fread

a = fread(path_to_csv, sep="|", nrows = 50)

How does it work internally?

The function fread does a few of things

  1. Reads the CSV using data.table::fread
  2. Saves the data.frame in feather format
  3. Loads the feather file into Julia as a DataFrame

Step 2 creates a feather file which you can set the location of by using a 2nd unnamed argument .e.g.

fread(path_to_csv, "path/to/out.feather")

by default the feather output path is path_to_csv*".feather i.e. with the feather extension attached to the input file.

Used By Packages

No packages found.