importAll: Function to Import and Concatenate Multiple data files

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Function to Import and Concatenate Multiple data files

Description

Imports multiple files into a list, concatenates them into a single table, and adds an 'fName' variable.

The files can be selected either by giving a file list (character vector), or by specifying a pattern.

Usage

importAll(
  path = ".",
  pattern = "",
  ignore.case = FALSE,
  importFunction = NULL,
  fill = FALSE,
  fileList = NULL
)

Arguments

path	Path to the directory, passed to 'list.files'.
pattern	Pattern to match file names, passed to 'list.files'.
ignore.case	Logical. If 'TRUE', ignores case when matching file names. Passed to 'list.files'. Default behavior is case-sensitive ('FALSE')
importFunction	A custom function for importing files. If not set, the function selects an import method based on the file extension.
fill	Logical. Passed to 'rbind' to allow filling missing columns.
fileList	A character vector of file names to import (used instead of 'pattern').

Value

A data frame containing the concatenated table with the fName column

Examples

# Directory containing test files
test_path <- tempdir()

# Create test files
write.csv( data.frame(a = 1:3, b = 4:6)    , file.path(test_path, "file1.csv"))
write.csv( data.frame(a = 7:9, b = 10:12)  , file.path(test_path, "file2.csv"))
write.csv( data.frame(a = 3:5, b = 8:10)   , file.path(test_path, "file3.csv"))
saveRDS(   data.frame(a = 1:5, b = 6:10)   , file.path(test_path, "file1.rds"))
saveRDS(   data.frame(a = 11:15, b = 16:20), file.path(test_path, "file2.rds"))

# Example 1 : Import all csv files
result <- importAll(path = test_path, pattern = "\\.csv$")
print(result)

# Example 2: Import only selected files
file_list <- c("file1.csv", "file2.csv")
result <- importAll(path = test_path, fileList = file_list)
print(result)

# Example 3: Import all .rds files
result <- importAll(path = test_path, pattern = "\\.rds$")
print(result)

# Example 4: Use a custom import function
custom_import <- function(file) {
  data <- read.csv(file, stringsAsFactors = FALSE)
  return(data)
}
result <- importAll(path = test_path, pattern = "\\.csv$", importFunction = custom_import)
print(result)

R.AlphA.Home documentation built on April 3, 2025, 5:53 p.m.