[R] Removing a dollar sign from a character vector

[William Dunlap]

   > y
   [1] "$1,000.00 " "$1,000.00 " "$1,000.00 " "$2,600.00 " "$2,600.00 "
   > gsub("$", "", y)
   [1] "$1,000.00 " "$1,000.00 " "$1,000.00 " "$2,600.00 " "$2,600.00 “ #
no change. Why?

"$" as a regular expression means "end of string", which has zero length -
replacing "end
of string" with nothing does not affect the string.  Try gsub("$",
"DOLLAR", "$100")
to see it do something.

Use either fixed=TRUE so the 'pattern'  argument is not regarded as a
regular expression or pattern="\\$" or pattern="[$]" to remove dollar's special
meaning in the pattern language.

Read up on regular expressions (probably there is a See Also entry in
help(gsub)).


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Feb 10, 2016 at 9:39 PM, James Plante <jimplante at me.com> wrote:

> What I’ve got:
> # sessionInfo()
> R version 3.2.3 (2015-12-10)
> Platform: x86_64-apple-darwin13.4.0 (64-bit)
> Running under: OS X 10.11.3 (El Capitan)
>
> locale:
> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
> [1] XML_3.98-1.3 dplyr_0.4.3
>
> loaded via a namespace (and not attached):
> [1] magrittr_1.5      R6_2.1.2          assertthat_0.1    rsconnect_0.4.1.4
> [5] parallel_3.2.3    DBI_0.3.1         tools_3.2.3       Rcpp_0.12.3
>
> > str(y) #toy vector, subset of larger vector in a dataframe of ~4,600
> rows.
>  chr [1:5] "$1,000.00 " "$1,000.00 " "$1,000.00 " "$2,600.00 " "$2,600.00 “
>
> y is a subset of a column in a dataframe that’s too big to post. I tried
> the commands listed here on the dataframe and it didn’t work. So I’m using
> a small subset to find out where my error is. It’s being a PITA, and I’m
> trying to solve it. What I want is a vector of numbers: 1000, 1000, 1000,
> 2600, 2,600.
>
> What I’ve tried:
> > y
> [1] "$1,000.00 " "$1,000.00 " "$1,000.00 " "$2,600.00 " "$2,600.00 "
> > gsub("$", "", y)
> [1] "$1,000.00 " "$1,000.00 " "$1,000.00 " "$2,600.00 " "$2,600.00 “ # no
> change. Why?
> > gsub(".00", "", y)  # note: that’s dot zero zero, replace with “"
> [1] "$10 " "$10 " "$10 " "$2, " "$2, “  #WTF?
>
> I’ve also tried sapply and apply, but haven’t yet tried a loop. (These
> were done in desperation; gsub ought to work the way the help says.) I’ve
> tried lots more than is listed here, over and over, with no results. I’d be
> grateful for any guidance you can provide.
>
> Thanks in advance,
>
> Jim Plante
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

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