[R] download.file error

[jim holtman]

?file.exists

On 4/1/08, CHIB CO <chibco at hotmail.com> wrote:
> Hi Jim,
>
> I just wanted to know if there is a function in R that can tell you whether
> a file on the internet exists before you attempt to download it or whether
> there is a way of handling the error you get in the download.file() function
> without having it break a for loop with the download error when it is part
> of that loop.
>
> Kind Regards
>
> Chib
>
>
> ________________________________
>
> > Date: Mon, 31 Mar 2008 18:33:35 -0500
> > From: jholtman at gmail.com
> > To: chibco at hotmail.com
> > Subject: Re: [R] download.file error
> > CC: r-help at r-project.org
>
> >
> > ?try
> >
> > On Mon, Mar 31, 2008 at 6:26 PM, CHIB CO <chibco at hotmail.com> wrote:
> > > Dear all,
> > >
> > > I am looking for a way to work out if a file on the internet exists
> before attempting to download it using the function download.file(). For
> example,
> > > using a url that does not exist
> > >
> > > url <- "http://finance.yahoo.com/ftse.csv"
> > > destfile <- tempfile()
> > > download.file(url = url, destfile = destfile)
> > >
> > > # gives the following response ...
> > >
> > > trying URL 'http://finance.yahoo.com/ftse.csv'
> > > Error in download.file(url = url, destfile = destfile) :
> > > cannot open URL 'http://finance.yahoo.com/ftse.csv'
> > > In addition: Warning message:
> > > In download.file(url = url, destfile = destfile) :
> > > cannot open: HTTP status was '404 Not Found'
> > >
> > > When I am using the download.file() function in a loop over multiple
> URLs, the above error will cause the loop to terminate, so I want to avoid
> this by checking if the file exists first then wrapping the subsequent
> functions in an if() statment. The original fault came from the function
> get.hist.quote() in the "tseries" package. I was trying to iterate over
> various stocks, but some stocks listed in the yahoo website do not have any
> downloadable data associated with them, which causes the loop to terminate.
> The "workhorse" function of get.hist.quote() is the download.file()
> function.
> > >
> > > Kind Regards
> > >
> > > Chib
> > >
> > >
> _________________________________________________________________
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> > >
> > >
> > > ______________________________________________
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> > > PLEASE do read the posting guide
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> > > and provide commented, minimal, self-contained, reproducible code.
> > >
> > >
> >
> >
> >
> > --
> > Jim Holtman
> > Cincinnati, OH
> > +1 513 646 9390
> >
> > What is the problem you are trying to solve?
>
>
> ________________________________
> Have you played Fishticuffs? Get fish-slapping on Messenger


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?