fst: Parse,inspect and extract data.table from fst file

In hope-data-science/tidydt: Tidy Verbs for 'data.table'

Description

An API for reading fst file as data.table.

Usage

parse_fst(path)

slice_fst(ft, row_no)

select_fst(ft, ...)

filter_fst(ft, ...)

Arguments

path	path to fst file
ft	An object of class fst_table, returned by parse_fst
row_no	An integer vector (Positive)
...	The filter conditions

Value

parse_fst returns a fst_table class.

select_fst and filter_fst returns a data.table.

See Also

fst

Examples

fst::write_fst(iris,"iris_fst_test.fst")

parse_fst("iris_fst_test.fst") -> ft
ft

ft %>% slice_fst(1:3)
ft %>% slice_fst(c(1,3))

ft %>% select_fst(Sepal.Length,Sepal.Width) # could not select only one in this way
ft %>% select_fst("Sepal.Length")
ft %>% select_fst(1:3)
ft %>% select_fst(1,3)
ft %>% select_fst("Se")
ft %>% select_fst("nothing")
ft %>% select_fst("Se|Sp")
ft %>% select_fst(names(iris)[2:3])

ft %>% filter_fst(Sepal.Width > 3)
ft %>% filter_fst(Sepal.Length > 6 , Species == "virginica")
ft %>% filter_fst(Sepal.Length > 6 & Species == "virginica" & Sepal.Width < 3)

rm(ft)
unlink("iris_fst_test.fst")

hope-data-science/tidydt documentation built on Feb. 21, 2020, 10:25 a.m.