rio: import_list – R documentation

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import_list

Import list of data frames

Description

Use import to import a list of data frames from a vector of file names or from a multi-object file (Excel workbook, .Rdata file, zip directory, or HTML file)

Usage

import_list(
  file,
  setclass,
  which,
  rbind = FALSE,
  rbind_label = "_file",
  rbind_fill = TRUE,
  ...
)

Arguments

`file`	A character string containing a single file name for a multi-object file (e.g., Excel workbook, zip directory, or HTML file), or a vector of file paths for multiple files to be imported.
`setclass`	An optional character vector specifying one or more classes to set on the import. By default, the return object is always a “data.frame”. Allowed values include “tbl_df”, “tbl”, or “tibble” (if using dplyr) or “data.table” (if using data.table). Other values are ignored, such that a data.frame is returned.
`which`	If `file` is a single file path, this specifies which objects should be extracted (passed to `import`'s `which` argument). Ignored otherwise.
`rbind`	A logical indicating whether to pass the import list of data frames through `rbindlist`.
`rbind_label`	If `rbind = TRUE`, a character string specifying the name of a column to add to the data frame indicating its source file.
`rbind_fill`	If `rbind = TRUE`, a logical indicating whether to set the `fill = TRUE` (and fill missing columns with `NA`).
`...`	Additional arguments passed to `import`. Behavior may be unexpected if files are of different formats.

Value

If rbind=FALSE (the default), a list of a data frames. Otherwise, that list is passed to rbindlist with fill = TRUE and returns a data frame object of class set by the setclass argument; if this operation fails, the list is returned.

Examples

library('datasets')
export(list(mtcars1 = mtcars[1:10,], 
            mtcars2 = mtcars[11:20,],
            mtcars2 = mtcars[21:32,]), "mtcars.xlsx")

# import a single file from multi-object workbook
str(import("mtcars.xlsx", which = "mtcars1"))

# import all worksheets
str(import_list("mtcars.xlsx"), 1)

# import and rbind all worksheets
mtcars2 <- import_list("mtcars.xlsx", rbind = TRUE)
all.equal(mtcars2, mtcars, check.attributes = FALSE)

# import multiple files
export(mtcars, "mtcars.csv")
export(mtcars, "iris.csv")
str(import_list(dir(pattern = "csv$")), 1)

# cleanup
unlink("mtcars.xlsx")
unlink("mtcars.csv")
unlink("iris.csv")

rio

A Swiss-Army Knife for Data I/O

v0.5.26

GPL-2

Authors

Jason Becker [ctb], Chung-hong Chan [aut], Geoffrey CH Chan [ctb], Thomas J. Leeper [aut, cre] (<https://orcid.org/0000-0003-4097-6326>), Christopher Gandrud [ctb], Andrew MacDonald [ctb], Ista Zahn [ctb], Stanislaus Stadlmann [ctb], Ruaridh Williamson [ctb], Patrick Kennedy [ctb], Ryan Price [ctb], Trevor L Davis [ctb], Nathan Day [ctb], Bill Denney [ctb] (<https://orcid.org/0000-0002-5759-428X>), Alex Bokov [ctb] (<https://orcid.org/0000-0002-0511-9815>)

Initial release

2021-02-22