Thanks for your help.
Ashwin
On Mon, Aug 12, 2013 at 10:38 AM, William Dunlap <wdun...@tibco.com> wrote:
> Because dir()'s pattern argument should be a 'regular expression'****
>
> and "*.xml" as a regular expression matches things you probably****
>
> do not want:****
>
> ** **
>
> > file.create(c("one.pxml", "two.xml", "wxml.three"))****
>
> [1] TRUE TRUE TRUE****
>
> > dir(pattern="*.xml")****
>
> [1] "one.pxml" "two.xml" "wxml.three"****
>
> > dir(pattern="\\.xml$")****
>
> [1] "two.xml"****
>
> ** **
>
> You a probably thinking of 'glob' patterns, akin to what is used****
>
> in DOS and Unix shells. You can use glob2rx to convert them to****
>
> regular expressions.****
>
> > glob2rx("*.xml")****
>
> [1] "^.*\\.xml$"****
>
> ** **
>
> Bill Dunlap****
>
> Spotfire, TIBCO Software****
>
> wdunlap tibco.com****
>
> ** **
>
> *From:* Ashwani Rao [mailto:ashwamegh1...@gmail.com]
> *Sent:* Monday, August 12, 2013 10:04 AM
> *To:* William Dunlap
> *Cc:* r-help@r-project.org
> *Subject:* Re: [R] function closure****
>
> ** **
>
> Thanks Bill.****
>
> Can you please tell me why did you change exp "pattern="*.xml"" to
> pattern="\\.xml$".****
>
> I know that second one also makes sense.****
>
> ** **
>
> ** **
>
> ** **
>
> On Mon, Aug 12, 2013 at 9:59 AM, William Dunlap <wdun...@tibco.com> wrote:
> ****
>
> Change your 'fileIndex <- fileIndex + 1' to 'fileIndex <<- fileIndex + 1'
> so the fileIndex in the environment of the call to generateFiles() is
> altered
> (instead of creating and forgetting about a variable called fileIndex
> in the function created by generateFiles.
>
> generateFiles <- function(path, pattern="\\.xml$") {
> files <- dir(path, pattern=pattern, full.names=TRUE, recursive=TRUE,
> no..=TRUE)****
>
> total <- length(files)
> fileindex <- 1
> fileGen <- function() {
> if (fileindex < total) {****
>
> fileToReturn <- files[[fileindex]]
> print(fileindex)
> fileindex <<- fileindex + 1****
>
> fileToReturn
> }
> }
> fileGen
> }
>
> used as:
>
> > nextFile <- generateFiles("c:/temp", pattern="\\.R$")
> > nextFile()
> [1] 1
> [1] "c:/temp/4209/test.R"
> > nextFile()
> [1] 2
> [1] "c:/temp/a.R"
>
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com****
>
>
>
> > -----Original Message-----
> > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org]
> On Behalf
> > Of Ashwani Rao
> > Sent: Monday, August 12, 2013 9:45 AM
> > To: r-help@r-project.org
> > Subject: [R] function closure
> >
> > Hi,
> >
> > Just for fun, I wanted to try function closures.
> > Here is simple function definition.
> > The following "generateFiles" function return function "fileGen" which
> will
> > return a a regular file in directory , every time a call it (fileGen).
> >
> >
> > generateFiles <- function(path, pattern="*.xml")
> >
> > {
> >
> > files <- dir(path, pattern="*.xml", full.names=TRUE,
> recursive=TRUE,
> > no..=TRUE)
> >
> > total <- length(files)
> >
> > fileindex = 1
> >
> > fileGen <- function()
> >
> > {
> >
> > if (fileindex > total)
> >
> > {
> >
> > return(NULL)
> >
> > }
> >
> > fileToReturn <- files[[fileindex]]
> >
> > print(fileindex)
> >
> > fileindex <- fileindex + 1
> >
> > return(fileToReturn)
> >
> > }
> >
> > return(fileGen)
> >
> > }
> >
> >
> > I am incrementing the value of variable "fileindex" in the function
> > "fileGen" , everytime I call this function.
> >
> > But the value of fileindex remains 1 , no matter how many times i call
> > "fileGen()".
> >
> > Can you please tell me how to change the value of fileIndex so as in
> > subsequent call to "fileGen" will reflect this.
> > --
> > à¤
शà¥à¤µà¤¨à¥ पà¥à¤°à¤¤à¤¾à¤ª
> >****
>
> > [[alternative HTML version deleted]]****
>
>
>
> ****
>
> ** **
>
> --
> à¤
शà¥à¤µà¤¨à¥ पà¥à¤°à¤¤à¤¾à¤ª ****
>
--
à¤
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