R help - Mar 2009 - gsub and regex to tidy comma-limited values

I am cleaning up comma-limited values, so that only one comma
separates each value. Using the example below, as much as I try with
regex, I can't remove the last comma. I hope to have a one-liner
solution, if possible.

gsub("^,*|,*$|(,)*", "\\1",
",,,apple,,orange,,,,,lemon,strawberry,,,,")
[1] "apple,orange,lemon,strawberry,"

Add perl = TRUE

On Sat, Mar 14, 2009 at 5:42 AM, Daren Tan <darentan76 at gmail.com>
wrote:
> I am cleaning up comma-limited values, so that only one comma
> separates each value. Using the example below, as much as I try with
> regex, I can't remove the last comma. I hope to have a one-liner
> solution, if possible.
>
> gsub("^,*|,*$|(,)*", "\\1",
",,,apple,,orange,,,,,lemon,strawberry,,,,")
> [1] "apple,orange,lemon,strawberry,"

sub(",$","",gsub("^,*|,*$|(,)*", "\\1", 
",,,apple,,orange,,,,,lemon,strawberry,,,,"))

It may not be the best solution, but it was my first thought

Tom

----- Original Message ----- 
From: "Daren Tan" <darentan76 at gmail.com>
To: <r-help at r-project.org>
Sent: Saturday, March 14, 2009 6:42 PM
Subject: [R] gsub and regex to tidy comma-limited values

>I am cleaning up comma-limited values, so that only one comma
> separates each value. Using the example below, as much as I try with
> regex, I can't remove the last comma. I hope to have a one-liner
> solution, if possible.
>
> gsub("^,*|,*$|(,)*", "\\1",
",,,apple,,orange,,,,,lemon,strawberry,,,,")
> [1] "apple,orange,lemon,strawberry,"
>
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