Re: [R] Dropping a digit with scan() on a connection
Thank you Dr. Ripley and Christoph Buser for your explanations and
help.
Using sep = " " within scan worked within lines of my file, but then I
gained an NA record when wrapping from one line to the next (because the
linebreak character is no longer recognized as a sep?). So, I'll
continue by ensuring each group I read ends at the end of a line (as
scan was designed), and by using scan without the sep option.
FYI, Here's how the NA showed up, each line is 800 numbers long:
>test4 <- scan(cn.test, n=1600, sep = " ")
>test5 <- scan(cn.test, n=1600)
>test4[797:803]
[1] 81.0 81.08746 81.89484 82.0NA 580.09030
576.90300
> test5[797:803]
[1] 81.01944 81.62060 81.96495 82.0 82.0 567.91840
563.10470
Thanks again.
Tim
>>> Prof Brian Ripley <[EMAIL PROTECTED]> 01/19/05 03:42AM >>>
This is because scan() has a private pushback.
Either:
1) Read the file a whole line at a time: I cannot see why you need to
do
so here nor in your sketched application.
or
2) Use an explicit separator, e.g. " " in your example.
scan() is not designed to read parts of lines of a file,
On Tue, 18 Jan 2005, Tim Howard wrote:
> R gurus,
>
> My use of scan() seems to be dropping the first digit of sequential
> scans on a connection. It looks like it happens only within a line:
>
>> cat("TITLE extra line", "235 335 535 735", "115 135 175",
> file="ex.data", sep="\n")
>> cn.x <- file("ex.data", open="r")
>> a <- scan(cn.x, skip=1, n=2)
> Read 2 items
>> a
> [1] 235 335
>> b <- scan(cn.x, n=2)
> Read 2 items
>> b
> [1] 35 735
>> c <- scan(cn.x, n=2)
> Read 2 items
>> c
> [1] 115 135
>> d <- scan(cn.x, n=1)
> Read 1 items
>> d
> [1] 75
>>
>
> Note in b, I should get 535, not 35 as the first value. In d, I
should
> get 175. Does anyone know how to get these digits?
>
> The reason I'm not scanning the entire file at once is that my real
> dataset is much larger than a Gig and I'll need to pull only portions
of
> the file in at once. I got readLines to work, but then I have to
figure
> out how to convert each entire line into a data.frame. Scan seems a
lot
> cleaner, with the exception of the funny character dropping issue.
>
> Thanks so much!
> Tim Howard
>
> __
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
--
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, UKFax: +44 1865 272595
__
R-help@stat.math.ethz.ch mailing list
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Re: [R] Dropping a digit with scan() on a connection
This is because scan() has a private pushback.
Either:
1) Read the file a whole line at a time: I cannot see why you need to do
so here nor in your sketched application.
or
2) Use an explicit separator, e.g. " " in your example.
scan() is not designed to read parts of lines of a file,
On Tue, 18 Jan 2005, Tim Howard wrote:
R gurus,
My use of scan() seems to be dropping the first digit of sequential
scans on a connection. It looks like it happens only within a line:
cat("TITLE extra line", "235 335 535 735", "115 135 175",
file="ex.data", sep="\n")
cn.x <- file("ex.data", open="r")
a <- scan(cn.x, skip=1, n=2)
Read 2 items
a
[1] 235 335
b <- scan(cn.x, n=2)
Read 2 items
b
[1] 35 735
c <- scan(cn.x, n=2)
Read 2 items
c
[1] 115 135
d <- scan(cn.x, n=1)
Read 1 items
d
[1] 75
Note in b, I should get 535, not 35 as the first value. In d, I should
get 175. Does anyone know how to get these digits?
The reason I'm not scanning the entire file at once is that my real
dataset is much larger than a Gig and I'll need to pull only portions of
the file in at once. I got readLines to work, but then I have to figure
out how to convert each entire line into a data.frame. Scan seems a lot
cleaner, with the exception of the funny character dropping issue.
Thanks so much!
Tim Howard
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
--
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, UKFax: +44 1865 272595
__
R-help@stat.math.ethz.ch mailing list
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PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Dropping a digit with scan() on a connection
Dear Tim
You can use
cat("TITLE extra line", "235 335 535 735", "115 135 175", file="ex.data",
sep="\n")
cn.x <- file("ex.data", open="r")
a <- scan(cn.x, skip=1, n=2, sep = " ")
> Read 2 items
a
> [1] 235 335
b <- scan(cn.x, n=2, sep = " ")
> Read 2 items
b
> [1] 535 735
c <- scan(cn.x, n=2, sep = " ")
> Read 2 items
c
> [1] 115 135
d <- scan(cn.x, n=1, sep = " ")
> Read 1 items
d
> [1] 175
Regards,
Christoph Buser
--
Christoph Buser <[EMAIL PROTECTED]>
Seminar fuer Statistik, LEO C11
ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
phone: x-41-1-632-5414 fax: 632-1228
http://stat.ethz.ch/~buser/
Tim Howard writes:
> R gurus,
>
> My use of scan() seems to be dropping the first digit of sequential
> scans on a connection. It looks like it happens only within a line:
>
> > cat("TITLE extra line", "235 335 535 735", "115 135 175",
> file="ex.data", sep="\n")
> > cn.x <- file("ex.data", open="r")
> > a <- scan(cn.x, skip=1, n=2)
> Read 2 items
> > a
> [1] 235 335
> > b <- scan(cn.x, n=2)
> Read 2 items
> > b
> [1] 35 735
> > c <- scan(cn.x, n=2)
> Read 2 items
> > c
> [1] 115 135
> > d <- scan(cn.x, n=1)
> Read 1 items
> > d
> [1] 75
> >
>
> Note in b, I should get 535, not 35 as the first value. In d, I should
> get 175. Does anyone know how to get these digits?
>
> The reason I'm not scanning the entire file at once is that my real
> dataset is much larger than a Gig and I'll need to pull only portions of
> the file in at once. I got readLines to work, but then I have to figure
> out how to convert each entire line into a data.frame. Scan seems a lot
> cleaner, with the exception of the funny character dropping issue.
>
> Thanks so much!
> Tim Howard
>
> __
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
