R help - Oct 2008 - Argh! Trouble using string data read from a file

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
-- 
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Sent from the R help mailing list archive at Nabble.com.

try putting as.character in the call:

x = read.csv(as.character(V4[[i]]), header = FALSE

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?