Create zip without extension

Question

I want to create a zip file named "out", not "out.zip". When I ran this line:

zip("out", zippedfiles) 

where zippedfiles is a list of files, I get out.zip . I am doing this in a windows environment.

Thanks.

Answer 1

Several people mentioned that this is zip behavior, but not why this is the reason you see it. If you look at the source for zip() or even help ?zip , you should immediately understand that the behavior you see comes from the zip function of the system and has nothing to do with R. All R is a call to the system function for zipping which is the default zip :

 R> zip function (zipfile, files, flags = "-r9X", extras = "", zip = Sys.getenv("R_ZIPCMD", "zip")) { if (missing(flags) && (!is.character(files) || !length(files))) stop("'files' must a character vector specifying one or more filepaths") args <- c(flags, shQuote(path.expand(zipfile)), shQuote(files), extras) invisible(system2(zip, args, invisible = TRUE)) ## simply calling system command } <bytecode: 0x27faf30> <environment: namespace:utils> 

If the extension annoys you, just call file.rename() after zip() :

 file.rename("out.zip", "out") 

Answer 2

For me, the extension is not used if I add . (i.e. period) to the file name, for example. out. must work. Full expression: zip("out.", zippedfiles) .

For what it's worth, this is due to the default zip behavior and is not a problem with R or Windows.

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Update 1: In general, it is best to avoid an OS-specific approach. I think this approach can cause problems if the code runs on other platforms. Gavin’s answer regarding renaming is more portable. What else, as I suggested in the comments, testing if the target exists using file.exists() adds another layer of security before renaming. An additional level of security is achieved by obtaining a temporary file name through tempfile() . An alternative way to avoid name clashes when writing or renaming is to use a timestamp in the name.