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rloops

Loop in R to read many files

I have been wondering if anybody knows a way to create a loop that loads files/databases in R. Say i have some files like that: data1.csv, data2.csv,..., data100.csv.

In some programming languages you one can do something like this data +{ x }+ .csv the system recognizes it like datax.csv, and then you can apply the loop.

Any ideas?

Solution

  • Sys.glob() is another possibility - it's sole purpose is globbing or wildcard expansion.

    dataFiles <- lapply(Sys.glob("data*.csv"), read.csv)

    That will read all the files of the form data[x].csv into list dataFiles, where [x] is nothing or anything.

    [Note this is a different pattern to that in @Joshua's Answer. There, list.files() takes a regular expression, whereas Sys.glob() just uses standard wildcards; which wildcards can be used is system dependent, details can be used can be found on the help page ?Sys.glob.]