[R] error message from read.csv in loop

[Kai Yang]

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





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