With list.files you can create a list of all the filenames in your workingdirectory. Next you can use lapply to loop over that list and read each file with the read_excel function from the readxl package:
library(readxl)
file.list <- list.files(pattern='*.xlsx')
df.list <- lapply(file.list, read_excel)
This method can off course also be used with other file reading functions like read.csv or read.table. Just replace read_excel with the appropriate file reading function and make sure you use the correct pattern in list.files.
If you also want to include the files in subdirectories, use:
file.list <- list.files(pattern='*.xlsx', recursive = TRUE)
Other possible packages for reading Excel-files: openxlsx & xlsx
Supposing the columns are the same for each file, you can bind them together in one dataframe with bind_rows from dplyr:
library(dplyr)
df <- bind_rows(df.list, .id = "id")
or with rbindlist from data.table:
library(data.table)
df <- rbindlist(df.list, idcol = "id")
Both have the option to add a id column for identifying the separate datasets.
Update: If you don’t want a numeric identifier, just use sapply with simplify = FALSE to read the files in file.list:
df.list <- sapply(file.list, read.csv, simplify=FALSE)
When using bind_rows from dplyr or rbindlist from data.table, the id column now contains the filenames.
Even another approach is using the purrr-package:
library(purrr)
file.list <- list.files(pattern='*.csv')
file.list <- setNames(file.list, file.list) # only needed when you need an id-column with the file-names
df <- map_df(file.list, read.csv, .id = "id")
Other approaches to getting a named list: If you don’t want just a numeric identifier, than you can assign the filenames to the dataframes in the list before you bind them together. There are several ways to do this:
# with the 'attr' function from base R
attr(df.list, "names") <- file.list
# with the 'names' function from base R
names(df.list) <- file.list
# with the 'setattr' function from the 'data.table' package
setattr(df.list, "names", file.list)
Now you can bind the list of dataframes together in one dataframe with rbindlist from data.table or bind_rows from dplyr. The id column will now contain the filenames instead of a numeric indentifier.