Dear Mac R folks,
I am not sure if this is a Mac specific problem or not, but it
certainly does not work on a Mac
Consider the data set
12345
23456
34567
45678
56789
copy this to the clipboard and then attempt to read it back in using
the read.fwf function
x <- read.fwf(file=pipe("pbpaste"),width=rep(1,5),header=FALSE)
The error is
Error in readLines(file, n = thisblock) : 'con' is not a connection
Error in UseMethod("close") :
no applicable method for 'close' applied to an object of class "NULL"
But if we try
y <- read.table(file=pipe("pbpaste"),header=FALSE)
That works (but of course does not separate the variables.
The help file for read.fwf says
file: the name of the file which the data are to be read from.
Alternatively, file can be a connection, which will be opened if
necessary, and if so closed at the end of the function call.
read.table says the same thing about file (but is a bit more wordy).
##
The problem seems to be in the lines 22 to 29 of read.fwf
if (is.character(file)) {
file <- file(file, "r")
on.exit(close(file), add = TRUE)
}
else if (!isOpen(file)) {
file <- open(file, "r")
on.exit(close(file), add = TRUE)
}
If we replace those lines with lines 10-21 of read.table then
read.fwf works as expected and will read from pipe("pbpaste")
if (is.character(file)) {
file <- if (nzchar(fileEncoding))
file(file, "rt", encoding = fileEncoding)
else file(file, "rt")
on.exit(close(file))
}
if (!inherits(file, "connection"))
stop("'file' must be a character string or connection")
if (!isOpen(file, "rt")) {
open(file, "rt")
on.exit(close(file))
}
I discovered this while trying to extend my read.clipboard function
to handle fixed format input.
The problem seems to happen on 2.10.1 as well as 2.11.0
R version 2.10.1 Patched (2009-12-16 r50763)
i386-apple-darwin9.8.0
locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] psych_1.0-86
loaded via a namespace (and not attached):
[1] tools_2.10.1
R version 2.11.0 Under development (unstable) (2010-02-12 r51122)
i386-apple-darwin9.8.0
locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] psych_1.0-86
Best wishes,
Bill
--
William Revelle http://personality-project.org/revelle.html
Professor http://personality-project.org
Department of Psychology http://www.wcas.northwestern.edu/psych/
Northwestern University http://www.northwestern.edu/
Use R for psychology http://personality-project.org/r
It is 6 minutes to midnight http://www.thebulletin.org
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