r - Read multiple CSV files into separate data frames

Question

Suppose we have files file1.csv, file2.csv, ... , and file100.csv in directory C:RData and we want to read them all into separate data frames (e.g. file1, file2, ... , and file100).

The reason for this is that, despite having similar names they have different file structures, so it is not that useful to have them in a list.

I could use lapply but that returns a single list containing 100 data frames. Instead I want these data frames in the Global Environment.

How do I read multiple files directly into the global environment? Or, alternatively, How do I unpack the contents of a list of data frames into it?

question from:https://stackoverflow.com/questions/5319839/read-multiple-csv-files-into-separate-data-frames

Answer 1

Thank you all for replying.

For completeness here is my final answer for loading any number of (tab) delimited files, in this case with 6 columns of data each where column 1 is characters, 2 is factor, and remainder numeric:

##Read files named xyz1111.csv, xyz2222.csv, etc.
filenames <- list.files(path="../Data/original_data",
    pattern="xyz+.*csv")

##Create list of data frame names without the ".csv" part 
names <-substr(filenames,1,7)

###Load all files
for(i in names){
    filepath <- file.path("../Data/original_data/",paste(i,".csv",sep=""))
    assign(i, read.delim(filepath,
    colClasses=c("character","factor",rep("numeric",4)),
    sep = ""))
}