On Wed, 15 Oct 2008, Ted Byers wrote:
Thanks Jim,
I hadn't seen the distinction between the commandline in RGui and what
happens within my code.
I have, however seen other differences I don't understand. For
example, looking at the documentation for RScript, I see:
Rscript [options] [-e expression] file [args]
And the example:
Rscript -e 'date()' -e 'format(Sys.time(), "%a %b %d %X %Y")'
So I tried it (Windows XP; R2.7.2), and this is what I got with just
copy directly from the documentation and pasting into the Windows
commandline window:
Your problem is the shell quoting: the Windows shell requires ". E.g.
C:\> d:/R/R-2.7.2/bin/Rscript -e "date()" -e "format(Sys.time(), \"%a %b %d %X
%Y\")"
[1] "Thu Oct 16 05:16:46 2008"
[1] "Thu Oct 16 05:16:46 2008"
Other shells (e.g. bash, tcsh) do allow '', and indeed that is the
preferred form there. See ?shQuote .
C:\>Rscript -e 'date()' -e 'format(Sys.time(), "%a %b %d %X %Y")'
[1] "date()"
C:\>Rscript -e 'format(Sys.time(), "%a %b %d %X %Y")'
C:\>
But within RGui, I get:
date();format(Sys.time(), "%a %b %d %X %Y")
[1] "Wed Oct 15 20:36:57 2008"
[1] "Wed Oct 15 8:36:57 PM 2008"
Thanks again
Ted
On Wed, Oct 15, 2008 at 8:09 PM, jim holtman <[EMAIL PROTECTED]> wrote:
You have to explicitly 'print' the value of x in the loop: print(x)
'x' by itself is just it value. At the command line, typing an
objects name is equivalent to printing that object, but it only
happens at the command line. If you want a value printed, the 'print'
it. Also works at the command line if you want to use it there also.
On Wed, Oct 15, 2008 at 5:36 PM, Ted Byers <[EMAIL PROTECTED]> wrote:
Actually, I'd tried single brackets first. Here is what I got:
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
the advice to use as.character worked, in that progress has been made.
Can you guys explain the following output, though?
setwd("K:\\MerchantData\\RiskModel\\AutomatedRiskModel")
for (i in 1:length(V4) ) { x = read.csv(as.character(V4[[i]]), header = FALSE,
na.strings="");x }
x
V1
1 0
x = read.csv(as.character(V4[[1]]), header = FALSE, na.strings="");x
V1
1 0
2 0
3 21
4 0
5 1
6 7
7 51
8 20
9 3
10 5
11 6
12 8
13 2
14 0
15 2
16 4
17 23
Clearly, if I hand write a line to read the data, getting the file
name from V4 (in this case V4[[1]]), I get the data into 'x', which I
can then display. I only displayed the first few as some of these
files will have thousands of values.
But what puzzles me is that I saw virtually no output from my loop. I
thought what would happen (with the x after the ';') is that the
contents of each file would be displayed after it is read and before
the first is read. And after the loop finishes, there is nothing in
x. I don't see why the contents of x would disappear after the loop,
unless R has scoping restrictions as stringent as, say, C++ (e.g. a
variable declared inside a loop is not visible outside the loop). But
that would beg the question as to how to declare a variable before it
is first used.
This doesn't bode well for me, or perhaps my ability to learn a new
trick at my age, when such a simple loop should give me such trouble.
:-(
Getting more grey hair by the minute. :-(
Thanks
ted
On Wed, Oct 15, 2008 at 5:12 PM, Rolf Turner <[EMAIL PROTECTED]> wrote:
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 <[EMAIL PROTECTED]> 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
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--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
______________________________________________
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______________________________________________
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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?
______________________________________________
[email protected] 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.
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
______________________________________________
[email protected] mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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