[R] readJPEG function cannot open jpeg files

[Duncan Murdoch]

On 13-01-14 11:59 AM, Yi Yuan wrote:
> Thanks William !
>
>   file.info("E:/ home work/Rstudio/kim.jpeg")
>                                         size isdir mode mtime ctime atime
>   exe
> E:/home work/Rstudio/kim.jpeg   NA    NA <NA>  <NA>  <NA>  <NA> <NA>
>
> So R thinks this file doesn't exist? But the file is already in "E:/ home
> work/Rstudio" folder, I don't understand why file.info( ) returned such
> message. I have multiple files in this directory "E:/home work/Rstudio",
> but R shows:
> file.info("E:/home work/Rstudio")
>                                           size isdir mode
> mtime               ctime               atime exe
> E:/home work/Rstudio    0  TRUE  777 2013-01-13 22:12:58 2013-01-13
> 20:57:36 2013-01-13 22:12:58  no
>
>   Any help ?

You seem to sometimes have spaces ahead of "home" and sometimes not.

What I recommend most people do on Windows is not to try to type the 
filename yourself, use file.choose() or choose.files() to get a dialog 
box and pick it out of there.

Duncan Murdoch

>
> On Mon, Jan 14, 2013 at 11:44 AM, William Dunlap <wdunlap at tibco.com> wrote:
>
>> You can use file.info("myFile") to make sure the file exists and has
>> appropriate permissions ("mode"
>> in file.info's lingo, as in Unix).  E.g.,
>>
>>> file.info("c:/temp/BO.jpeg") # this one does not exist
>>                  size isdir mode mtime ctime atime  exe
>> c:/temp/BO.jpeg   NA    NA <NA>  <NA>  <NA>  <NA> <NA>
>>> file.info("c:/temp/BO.jpg") # this one exists
>>                   size isdir mode               mtime               ctime
>>              atime
>> c:/temp/BO.jpg 150536 FALSE  666 2013-01-14 08:35:32 2013-01-14 08:33:09
>> 2013-01-14 08:33:09
>>                 exe
>> c:/temp/BO.jpg  no
>>
>> I can readJPEG() the file with mode 666, but not all permission
>> information is encoded in the mode.
>>
>> Bill Dunlap
>> Spotfire, TIBCO Software
>> wdunlap tibco.com
>>
>>> -----Original Message-----
>>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>> On Behalf
>>> Of Jeff Newmiller
>>> Sent: Monday, January 14, 2013 8:25 AM
>>> To: Yi Yuan; r-help at r-project.org
>>> Subject: Re: [R] readJPEG function cannot open jpeg files
>>>
>>> Being unable to open a file is a related to your operating system and
>> how R interacts with
>>> that OS. If your interactive development environment (IDE, of which
>> RStudio is an
>>> example) is trying to make things simpler for you but you don't
>> understand how to use it,
>>> then you need to ask help from your RStudio support resources, not here.
>>>
>>> When posting here, you should mention your results from using base R
>> functions like
>>>
>>> ?sessionInfo
>>> ?getwd
>>> ?list.files
>>>
>>> as indicated in the Posting Guide mentioned at the bottom of every
>> R-help email.
>>>
>>> Consistent with the fact that this is an interface issue between R and
>> the OS, sometimes
>>> you will have to investigate the problem from outside R. For example,
>> you might need to
>>> investigate issues with security permissions that are OS specific and
>> completely outside
>>> the scope of this forum.
>>>
>> ---------------------------------------------------------------------------
>>> Jeff Newmiller                        The     .....       .....  Go
>> Live...
>>> DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live
>> Go...
>>>                                        Live:   OO#.. Dead: OO#..  Playing
>>> Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
>>> /Software/Embedded Controllers)               .OO#.       .OO#.
>>   rocks...1k
>>>
>> ---------------------------------------------------------------------------
>>> Sent from my phone. Please excuse my brevity.
>>>
>>> Yi Yuan <lambandme at gmail.com> wrote:
>>>
>>>> I installed jpeg package and tried to use
>>>>
>>>> kim<-readJPEG("kim.jpeg") to read in a jpeg file, but R gave me an
>>>> error:
>>>> Error in readJPEG("kim.jpeg") : unable to open kim.jpeg
>>>>
>>>> I already put "kim.jpeg" in Rstudio's default working directory:
>>>> "E:\home
>>>> work\Rstudio". So I don't think it's a problem caused by omitting the
>>>> file's
>>>> path. But I tried with the full path version just in case and still got
>>>> the
>>>> "unable to open" error:
>>>>
>>>> kim<-readJPEG("E:\\ home work\\Rstudio\\kim.jpeg")
>>>> Error in readJPEG("E:\\ home work\\Rstudio\\kim.jpeg") :
>>>>   unable to open E:\ home work\Rstudio\kim.jpeg
>>>>
>>>> So now I really don't know what is wrong.
>>>>
>>>>      [[alternative HTML version deleted]]
>>>>
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>