An API for reading fst file as data.table.
parse_fst(path) slice_fst(ft, row_no) select_fst(ft, ...) filter_fst(ft, ...)
path | path to fst file |
---|---|
ft | An object of class fst_table, returned by |
row_no | An integer vector (Positive) |
... | The filter conditions |
parse_fst
returns a fst_table class.
select_fst
and filter_fst
returns a data.table.
if (FALSE) { fst::write_fst(iris,"iris_test.fst") # parse the file but not reading it parse_fst("iris_test.fst") -> ft ft # get the data by query ft %>% slice_fst(1:3) ft %>% slice_fst(c(1,3)) ft %>% select_fst(Sepal.Length) ft %>% select_fst(Sepal.Length,Sepal.Width) 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) unlink("iris_test.fst") }