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Compute results to a CSV file

Source: R/compute_csv.R
compute_csv.Rd

For a duckplyr frame, this function executes the query and stores the results in a CSV file, without converting it to an R data frame. The result is a duckplyr frame that can be used with subsequent dplyr verbs. This function can also be used as a CSV writer for regular data frames.

Usage

compute_csv(x, path, ..., prudence = NULL, options = NULL)

Arguments

x

A duckplyr frame.

path

The path of the Parquet file to create.

...

These dots are for future extensions and must be empty.

prudence

Memory protection, controls if DuckDB may convert intermediate results in DuckDB-managed memory to data frames in R memory.

  • "lavish": regardless of size,

  • "stingy": never,

  • "thrifty": up to a maximum size of 1 million cells.

The default is to inherit from the input. This argument is provided here only for convenience. The same effect can be achieved by forwarding the output to as_duckdb_tibble() with the desired prudence. See vignette("prudence") for more information.

options

A list of additional options to pass to create the storage format, see https://duckdb.org/docs/sql/statements/copy.html#csv-options for details.

Value

A duckplyr frame.

See also

compute_parquet(), compute.duckplyr_df(), dplyr::collect()

Examples

library(duckplyr)
df <- data.frame(x = c(1, 2))
df <- mutate(df, y = 2)
path <- tempfile(fileext = ".csv")
df <- compute_csv(df, path)
readLines(path)
#> [1] "x,y"     "1.0,2.0" "2.0,2.0"