excluding on element from a list

I am making a list of all the files in a folder and I want to exclude
one file called "proj.current". ?This is the 31st file in a folder.
Currently I use the command:

tdirs <- list.files(pattern="proj.")[-31]

However I would like to exclude it based on its name and not the

position.

You need to update the pattern in the regular expression to look for
strings beginning with "proj.", but not having "current" afterwards.

My first thought was to use perl style regular expressions, but apprently
this isn't supported.
tdirs <- list.files(pattern = "proj\\.(?!current)", perl=TRUE) ? #Throws
error

Instead, you're probably better off doing it in two steps.
tdirs <- list.files(pattern="proj\\.")
tdirs <- tdirs[tdirs != "proj.current"]

Notice the difference between "proj." and "proj\\.". ?The first means
'proj followed by any character', and the second means 'proj followed by a
dot'. ?See http://www.regular-expressions.info/quickstart.html for more
info on regexes.

Regards,
Richie.

Mathematical Sciences Unit
HSL


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