duckdb: duckdb_read_csv – R documentation

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duckdb_read_csv

Reads a CSV file into DuckDB

Description

Directly reads a CSV file into DuckDB, tries to detect and create the correct schema for it. This usually is much faster than reading the data into R and writing it to DuckDB.

Usage

duckdb_read_csv(
  conn,
  name,
  files,
  header = TRUE,
  na.strings = "",
  nrow.check = 500,
  delim = ",",
  quote = "\"",
  col.names = NULL,
  lower.case.names = FALSE,
  sep = delim,
  transaction = TRUE,
  ...
)

Arguments

`conn`	A DuckDB connection, created by `dbConnect()`.
`name`	The name for the virtual table that is registered or unregistered
`files`	One or more CSV file names, should all have the same structure though
`header`	Whether or not the CSV files have a separate header in the first line
`na.strings`	Which strings in the CSV files should be considered to be NULL
`nrow.check`	How many rows should be read from the CSV file to figure out data types
`delim`	Which field separator should be used
`quote`	Which quote character is used for columns in the CSV file
`col.names`	Override the detected or generated column names
`lower.case.names`	Transform column names to lower case
`sep`	Alias for delim for compatibility
`transaction`	Should a transaction be used for the entire operation
`...`	Passed on to `read.csv()`

Value

The number of rows in the resulted table, invisibly.

Examples

con <- dbConnect(duckdb())

data <- data.frame(a = 1:3, b = letters[1:3])
path <- tempfile(fileext = ".csv")

write.csv(data, path, row.names = FALSE)

duckdb_read_csv(con, "data", path)
dbReadTable(con, "data")

dbDisconnect(con)

duckdb

DBI Package for the DuckDB Database Management System

v0.2.6

MPL

Authors

Hannes Mühleisen [aut, cre] (<https://orcid.org/0000-0001-8552-0029>), Mark Raasveldt [aut] (<https://orcid.org/0000-0001-5005-6844>), DuckDB Contributors [aut], Apache Software Foundation [cph], PostgreSQL Global Development Group [cph], The Regents of the University of California [cph], Cameron Desrochers [cph], Victor Zverovich [cph], RAD Game Tools [cph], Valve Software [cph], Rich Geldreich [cph], Tenacious Software LLC [cph], The RE2 Authors [cph], Google Inc. [cph], Facebook Inc. [cph], Steven G. Johnson [cph], Jiahao Chen [cph], Tony Kelman [cph], Jonas Fonseca [cph], Lukas Fittl [cph], Salvatore Sanfilippo [cph], Art.sy, Inc. [cph], Oran Agra [cph], Redis Labs, Inc. [cph], Melissa O'Neill [cph], PCG Project contributors [cph]

Initial release