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Compute results to a CSV file

Source: R/compute_csv.R
compute_csv.Rd

This is a generic function that executes a query and stores the results in a CSV file. For a duckplyr frame, the materialization occurs outside of R. The result is a duckplyr frame that can be used with subsequent dplyr verbs.

Usage

compute_csv(x, path, ...)

# S3 method for class 'duckplyr_df'
compute_csv(x, path, ..., prudence = NULL, options = NULL)

# S3 method for class 'data.frame'
compute_csv(x, path, ..., prudence = NULL, options = NULL)

Arguments

x

A data frame or lazy data frame.

path

The path of the CSV file to create.

...

Additional arguments passed to methods.

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 data frame (the class may vary based on the input).

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"