R help - May 2009 - Way to handle variable length and numbers of columns using read.table(...)

I've got read.table to successfully read in my table of three columns.  Most
of the time I will have a set number of rows, but sometime that will be variable
and sometimes there will be only be two variables in one row, e.g.

Time Loc1 Loc2
1 22.33 44.55
2 66.77 88.99
3 222.33344.55
4 66.77 88.99

Is there any way to have read.table handle (1) a variable number of rows, and
(2) sometime there are only two variables as shown in Time = 3 above?

Just curious about how to handle this, and if read.table is the right way to go
about or if I should read in all the data and then try to parse it out best I
can.

Thanks again.
> R.version
               _                           
platform       i386-apple-darwin8.11.1     
arch           i386                        
os             darwin8.11.1                
system         i386, darwin8.11.1          
status                                     
major          2                           
minor          8.0                         
year           2008                        
month          10                          
day            20                          
svn rev        46754                       
language       R                           
version.string R version 2.8.0 (2008-10-20)

Well if you read in your data, you get:
> x <- read.table('clipboard', header=TRUE, fill=TRUE)
Warning message:
In read.table("clipboard", header = TRUE, fill = TRUE) :
  incomplete final line found by readTableHeader on
'clipboard'
> x
  Time         Loc1  Loc2
1    1        22.33 44.55
2    2        66.77 88.99
3    3 222.33344.55    NA
4    4        66.77 88.99
> str(x)
'data.frame':   4 obs. of  3 variables:
 $ Time: int  1 2 3 4
 $ Loc1: Factor w/ 3 levels "22.33","222.33344.55",..: 1 3 2
3
 $ Loc2: num  44.5 89 NA 89
>
As you can see the variable that has two decimal points is read in as a
character and cause the whole column to be converted to a factor.  It
appears that you have some fixed length fields that are overflowing.  Now
you could read in the data and use regualr expressions and parse the data;
you just have to match on the first part have two decimal place and then
extract the rest.  THe question is, is this the only "problems" you
have in
the data?  If so, parsing it is not hard.

On Mon, May 4, 2009 at 10:20 PM, Jason Rupert
<jasonkrupert@yahoo.com>wrote:
>
> I've got read.table to successfully read in my table of three columns.
>  Most of the time I will have a set number of rows, but sometime that will
> be variable and sometimes there will be only be two variables in one row,
> e.g.
>
> Time Loc1 Loc2
> 1 22.33 44.55
> 2 66.77 88.99
> 3 222.33344.55
> 4 66.77 88.99
>
> Is there any way to have read.table handle (1) a variable number of rows,
> and (2) sometime there are only two variables as shown in Time = 3 above?
>
> Just curious about how to handle this, and if read.table is the right way
> to go about or if I should read in all the data and then try to parse it
out
> best I can.
>
> Thanks again.
>
> > R.version
>               _
> platform       i386-apple-darwin8.11.1
> arch           i386
> os             darwin8.11.1
> system         i386, darwin8.11.1
> status
> major          2
> minor          8.0
> year           2008
> month          10
> day            20
> svn rev        46754
> language       R
> version.string R version 2.8.0 (2008-10-20)
>
> ______________________________________________
> R-help@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<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?

	[[alternative HTML version deleted]]

Its not clear exactly what the rules are for this but if we assume
that numbers always end in a decimal plus two digits then
using stapply from the gsubfn package:
> Lines <- "Time Loc1 Loc2
+ 1 22.33 44.55
+ 2 66.77 88.99
+ 3 222.33344.55
+ 4 66.77 88.99"
>
> library(gsubfn)
> L <- readLines(textConnection(Lines))
> strapply(L[-1], "[0-9]*[.][0-9][0-9]", as.numeric, simplify =
rbind)
       [,1]   [,2]
[1,]  22.33  44.55
[2,]  66.77  88.99
[3,] 222.33 344.55
[4,]  66.77  88.99

See http://gsubfn.googlecode.com and for regular expressions see ?regex

On Mon, May 4, 2009 at 10:20 PM, Jason Rupert <jasonkrupert at yahoo.com>
wrote:
>
> I've got read.table to successfully read in my table of three columns.
?Most of the time I will have a set number of rows, but sometime that will be
variable and sometimes there will be only be two variables in one row, e.g.
>
> Time Loc1 Loc2
> 1 22.33 44.55
> 2 66.77 88.99
> 3 222.33344.55
> 4 66.77 88.99
>
> Is there any way to have read.table handle (1) a variable number of rows,
and (2) sometime there are only two variables as shown in Time = 3 above?
>
> Just curious about how to handle this, and if read.table is the right way
to go about or if I should read in all the data and then try to parse it out
best I can.
>
> Thanks again.
>
>> R.version
> ? ? ? ? ? ? ? _
> platform ? ? ? i386-apple-darwin8.11.1
> arch ? ? ? ? ? i386
> os ? ? ? ? ? ? darwin8.11.1
> system ? ? ? ? i386, darwin8.11.1
> status
> major ? ? ? ? ?2
> minor ? ? ? ? ?8.0
> year ? ? ? ? ? 2008
> month ? ? ? ? ?10
> day ? ? ? ? ? ?20
> svn rev ? ? ? ?46754
> language ? ? ? R
> version.string R version 2.8.0 (2008-10-20)
>
> ______________________________________________
> 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.
>