从fst到data.table

从fst文件中解析、检查和提取data.table对象

描述

一个用于将fst文件读取为data.table的api工具包，可以按列、行选择和条件筛选去选择

Usage

parse_fst(path)

slice_fst(ft, row_no)

select_fst(ft, …)

filter_fst(ft, …)

summary_fst(ft)

Arguments

library(tidyfst)
fst::write_fst(iris,"iris_test.fst")
# parse the file but not reading it
parse_fst("iris_test.fst") -> ft
ft
class(ft)
lapply(ft,class)
names(ft)
dim(ft)
summary_fst(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(cols = 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")