14  data.table Data I/O

14.1 Read delimited data with fread()

data.table’s “fast read” function fread() offers a replacement for the base read.csv() command. By default, it creates a data.table object, which is likely preferred in most scenarios, but it can create a data.frame by setting data.table = FALSE.

It is very useful because it allows:

• very fast, parallelized reading of large delimited files, e.g. with millions of rows
• can directly read zipped files
• smart automatic discovery of delimiters when sep = "auto" (default)
• multiple other conveniences

As an example, you can read a gzipped file directly from a URL:

library(data.table)
bcw <- fread("https://github.com/EpistasisLab/penn-ml-benchmarks/raw/master/datasets/classification/breast-cancer-wisconsin/breast-cancer-wisconsin.tsv.gz")

14.1.1 See also

Convenience features of fread

14.2 Write delimited data with fwrite()

fwrite() similarly provides a faster, parallelized, and more flexible replacement for write.csv():

fwrite(dat, "/path/to/file.csv")