write.fst {fst} | R Documentation |
Read and write data frames from and to a fast-storage (fst) file.
Allows for compression and (file level) random access of stored data, even for compressed datasets.
When using a data.table
object for x
, the key (if any) is preserved, allowing storage of sorted data.
write.fst(x, path, compress = 0) read.fst(path, columns = NULL, from = 1, to = NULL, as.data.table = FALSE)
x |
A data frame to write to disk |
path |
Path to fst file |
compress |
Value in the range 0 to 100, indicating the amount of compression to use. |
columns |
Column names to read. The default is to read all all columns. |
from |
Read data starting from this row number. |
to |
Read data up until this row number. The default is to read to the last row of the stored dataset. |
as.data.table |
If TRUE, the result will be returned as a |
Both functions return a data frame. write.fst
invisibly returns x
(so you can use this function in a pipeline).
# Sample dataset x <- data.frame(A = 1:10000, B = sample(c(TRUE, FALSE, NA), 10000, replace = TRUE)) # Uncompressed write.fst(x, "dataset.fst") # filesize: 41 KB y <- read.fst("dataset.fst") # read uncompressed data # Compressed write.fst(x, "dataset.fst", 100) # fileSize: 4 KB y <- read.fst("dataset.fst") # read compressed data # Random access y <- read.fst("dataset.fst", "B") # read selection of columns y <- read.fst("dataset.fst", "A", 100, 200) # read selection of columns and rows