[R] Argh! Trouble using string data read from a file

[Rolf Turner]

On 16/10/2008, at 10:03 AM, jim holtman wrote:

> try putting as.character in the call:
>
> x = read.csv(as.character(V4[[i]]), header = FALSE

No.  This won't help.  V4 is a column of the data frame optdata,
and hence is a vector.  Not a list!  Use single brackets --- V4[i] ---
and all will be well.

	cheers,

		Rolf
>
> On Wed, Oct 15, 2008 at 4:46 PM, Ted Byers <r.ted.byers at gmail.com>  
> wrote:
>>
>> Here is what I tried:
>>
>> optdata =
>> read.csv("K:\\MerchantData\\RiskModel\\AutomatedRiskModel\ 
>> \soptions.dat",
>> header = FALSE, na.strings="")
>> optdata
>> attach(optdata)
>> for (i in 1:length(V4) ) { x = read.csv(V4[[i]], header = FALSE,
>> na.strings="");x }
>>
>> And here  is the outcome (just a few of the 60 records  
>> successfully read):
>>> optdata =
>>> read.csv("K:\\MerchantData\\RiskModel\\AutomatedRiskModel\ 
>>> \soptions.dat",
>>> header = FALSE, na.strings="")
>>> optdata
>>    V1   V2 V3                        V4
>> 1  251 2008 18 Plus_Shipping.2008.18.dat
>> 2  251 2008 19 Plus_Shipping.2008.19.dat
>> 3  251 2008 20 Plus_Shipping.2008.20.dat
>> 4  251 2008 22 Plus_Shipping.2008.22.dat
>> 5  251 2008 23 Plus_Shipping.2008.23.dat
>> 6  251 2008 24 Plus_Shipping.2008.24.dat
>>
>> I can see the data has been correctly read.  But for some reason  
>> that isn't
>> clear, read.csv doesn't like the data in the last column.
>>
>>> attach(optdata)
>>> for (i in 1:length(V4) ) { x = read.csv(V4[[i]], header = FALSE,
>>> na.strings="");x }
>> Error in read.table(file = file, header = header, sep = sep, quote  
>> = quote,
>> :
>>  'file' must be a character string or connection
>>> V4[[1]]
>> [1] Plus_Shipping.2008.18.dat
>> 60 Levels: Easyway.2008.17.dat Easyway.2008.18.dat Easyway. 
>> 2008.19.dat
>> Easyway.2008.20.dat ... Secured_Pay.2008.31.dat
>>
>>>
>>
>> The last column is comprised of valid Windows filenames (and no  
>> whitespace,
>> so as not to confuse things).
>>
>> I see in the docuentation "`[[...]]' is the operator used to  
>> select a single
>> element, whereas `[...]' is a general subscripting operator.", so  
>> I assume
>> V4[[i]] is the correct way to get the ith value from V4.  So why does
>> read.csv complain that "'file' must be a character string or  
>> connection"?
>> It seems obvious that the value in V4[[i]i] is a string.  V4[[1]]  
>> does give
>> me the right value, although that is followed by output I didn't  
>> ask for.
>>
>> In the loop above, I was going to replace the output obtained by  
>> 'x' with
>> output from fitdistr(x,"exponential"), but I can't proceed with  
>> that until I
>> can get the data in these files read.
>>
>> What have I missed?
>>
>> Thanks
>>
>> Ted
>> --
>> View this message in context: http://www.nabble.com/Argh%21-- 
>> Trouble-using-string-data-read-from-a-file-tp20002064p20002064.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> 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.
>>
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>
> ______________________________________________
> 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.


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