r-data-formats

R Data Formats

Reading and writing various data formats.

CSV/TSV

# readr (tidyverse)
library(readr)
df <- read_csv("data.csv")
df <- read_tsv("data.tsv")
df <- read_delim("data.txt", delim = "|")
write_csv(df, "output.csv")

# vroom (faster for large files)
library(vroom)
df <- vroom("data.csv")
df <- vroom(c("file1.csv", "file2.csv"))  # Multiple files

# Base R
df <- read.csv("data.csv", stringsAsFactors = FALSE)
write.csv(df, "output.csv", row.names = FALSE)

# data.table (fastest)
library(data.table)
dt <- fread("data.csv")
fwrite(dt, "output.csv")

Excel

# Read
library(readxl)
df <- read_excel("data.xlsx")
df <- read_excel("data.xlsx", sheet = "Sheet2")
df <- read_excel("data.xlsx", range = "A1:D100")
excel_sheets("data.xlsx")  # List sheets

# Write
library(writexl)
write_xlsx(df, "output.xlsx")
write_xlsx(list(sheet1 = df1, sheet2 = df2), "output.xlsx")

# openxlsx (more features)
library(openxlsx)
wb <- createWorkbook()
addWorksheet(wb, "Data")
writeData(wb, "Data", df)
saveWorkbook(wb, "output.xlsx")

JSON

library(jsonlite)

# Read
df <- fromJSON("data.json")
data <- fromJSON('{"name": "test", "value": 123}')

# Write
json <- toJSON(df, pretty = TRUE)
write_json(df, "output.json")

# API responses
resp <- httr::GET("https://api.example.com/data")
data <- fromJSON(httr::content(resp, "text"))

Arrow/Parquet

library(arrow)

# Parquet (columnar, compressed)
df <- read_parquet("data.parquet")
write_parquet(df, "output.parquet")

# Feather (fast binary)
df <- read_feather("data.feather")
write_feather(df, "output.feather")

# Arrow datasets (large/partitioned)
ds <- open_dataset("data_dir/", format = "parquet")
ds %>% filter(x > 10) %>% collect()

Fast Serialization

# fst (fastest for data frames)
library(fst)
write_fst(df, "data.fst", compress = 100)
df <- read_fst("data.fst")
df <- read_fst("data.fst", columns = c("a", "b"))

# qs (general R objects)
library(qs)
qsave(obj, "data.qs")
obj <- qread("data.qs")

# RDS (base R)
saveRDS(obj, "data.rds")
obj <- readRDS("data.rds")