[R] error message from read.csv in loop

[Migdonio González]

Thank you very much for the clarification. I will try to use a more precise
language next time.

Warm regards
Migdonio G.

On Sat, Jul 10, 2021 at 11:30 AM Bert Gunter <bgunter.4567 using gmail.com> wrote:

> "It seems that your problem is that you are using single quotes inside of
> the double quotes."
>
> That is FALSE. From ?Quotes:
> "Single and double quotes delimit character constants. They can be
> used interchangeably but double quotes are preferred (and character
> constants are printed using double quotes), so single quotes are
> normally only used to delimit character constants containing double
> quotes."
>
> Of course, pairs of each type of quote must properly match, must not
> get confused with quotes in the delineated string, etc. , but they are
> otherwise interchangeable. The whole of ?Quotes, especially the
> examples, is informative and worth the read (imo).
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>
> On Sat, Jul 10, 2021 at 8:20 AM Migdonio González
> <migdonio.gonzalez02 using gmail.com> wrote:
> >
> >  It seems that your problem is that you are using single quotes inside of
> > the double quotes. This is not necessary. Here is the corrected for-loop:
> >
> > for (j in 1:nrow(ora))
> > {
> >         mycol  <- ora[j,"fname"]
> >         mycsv  <- paste0(mycol,".csv")
> >         rdcsv  <- noquote(paste0("w:/project/_Joe.B/Oracle/data/",
> mycsv))
> >         rr     <- read.csv(rdcsv)
> > }
> >
> > Also note that the rr variable will only store the last CSV, not all CSV.
> > You will need to initialize the rr variable as a list to store all CSVs
> if
> > that is what you require. Something like this:
> >
> > # Initialize the rr variable as a list.
> > rr <- as.list(rep(NA, nrow(ora)))
> >
> > # Run the for-loop to store all the CSVs in rr.
> > for (j in 1:nrow(ora))
> > {
> >         mycol  <- ora[j,"fname"]
> >         mycsv  <- paste0(mycol,".csv")
> >         rdcsv  <- noquote(paste0("w:/project/_Joe.B/Oracle/data/",
> mycsv))
> >         rr[[j]]     <- read.csv(rdcsv)
> > }
> >
> > Regards
> > Migdonio G.
> >
> > On Fri, Jul 9, 2021 at 1:10 PM Kai Yang via R-help <r-help using r-project.org
> >
> > wrote:
> >
> > > Hello List,
> > > I use for loop to read csv difference file into data frame rr.  The
> data
> > > frame rr will be deleted after a comparison and go to the next csv
> file.
> > > Below is my code:
> > > for (j in 1:nrow(ora))
> > > {
> > >   mycol  <- ora[j,"fname"]
> > >   mycsv  <- paste0(mycol,".csv'")
> > >   rdcsv  <- noquote(paste0("'w:/project/_Joe.B/Oracle/data/", mycsv))
> > >   rr     <- read.csv(rdcsv)
> > > }
> > > but when I run this code, I got error message below:
> > > Error in file(file, "rt") : cannot open the connection
> > > In addition: Warning message:
> > > In file(file, "rt") :
> > >   cannot open file
> > > ''w:/project/_Joe.B/Oracle/data/ASSAY_DEFINITIONS.csv'': No such file
> or
> > > directory
> > >
> > > so, I checked the rdcsv and print it out, see below:
> > > [1] 'w:/project/_Joe.B/Oracle/data/ASSAY_DEFINITIONS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/ASSAY_DISCRETE_VALUES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/ASSAY_QUESTIONS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/ASSAY_RUNS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/DATA_ENTRY_PAGES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/DISCRETE_VALUES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/ENTRY_GROUPS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/GEMD_CODELIST_GROUPS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/GEMD_CODELIST_VALUES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/GEMD_LOT_DEFINITIONS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/GEMD_SAMPLES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/MOLECULAR_WAREHOUSE.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/QUESTION_DEFINITIONS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/QUESTION_GROUPS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/RESPONDENTS.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/RESPONSES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/SAMPLE_LIST.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/SAMPLE_LIST_NAMES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/SAMPLE_PLATE_ADDRESSES.csv'
> > > [1] 'w:/project/_Joe.B/Oracle/data/STORAGE_UNITS.csv'
> > > it seems correct. I copy and paste it into a code :
> > >  rr     <- read.csv( 'w:/project/_Joe.B/Oracle/data/RESPONDENTS.csv')
> > > and it works fine.
> > > Can someone help me debug where is the problem in my for loop code?
> > > Thanks,
> > > Kai
> > >
> > >
> > >
> > >
> > >
> > >         [[alternative HTML version deleted]]
> > >
> > > ______________________________________________
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> > > PLEASE do read the posting guide
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> > > and provide commented, minimal, self-contained, reproducible code.
> > >
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>

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