[R] read.table input array

[jim holtman]

Here is a way of creating a separate list of variable length vectors
that you can use in your processing:

> # read into a dataframe
> x <- read.table(textConnection("A    B    C    T    Lengths
+ 1    4.0    0.0015258789    18    c(1,2,3)
+ 1    4.0    0.0015258789    18    c(1,2,6,7,8,3)
+ 1    4.0    0.0015258789    18    c(1,2,3,1,2,3,4,5,6,7,9)
+ 1    4.0    0.0015258789    18    c(1,2,3)
+ 1    1.0    0.0017166138    24    c(1,1,4)"), header=TRUE)
> # create a  'list' with the variable length vectors
> # assuming the the "Lengths" are legal R expressions using 'c'
> x$varList <- lapply(x$Lengths, function(a) eval(parse(text=a)))
>
> x
  A B           C  T                  Lengths                         varList
1 1 4 0.001525879 18                 c(1,2,3)                         1, 2, 3
2 1 4 0.001525879 18           c(1,2,6,7,8,3)                1, 2, 6, 7, 8, 3
3 1 4 0.001525879 18 c(1,2,3,1,2,3,4,5,6,7,9) 1, 2, 3, 1, 2, 3, 4, 5, 6, 7, 9
4 1 4 0.001525879 18                 c(1,2,3)                         1, 2, 3
5 1 1 0.001716614 24                 c(1,1,4)                         1, 1, 4
> str(x)
'data.frame':   5 obs. of  6 variables:
 $ A      : int  1 1 1 1 1
 $ B      : num  4 4 4 4 1
 $ C      : num  0.00153 0.00153 0.00153 0.00153 0.00172
 $ T      : int  18 18 18 18 24
 $ Lengths: Factor w/ 4 levels "c(1,1,4)","c(1,2,3)",..: 2 4 3 2 1
 $ varList:List of 5
  ..$ : num  1 2 3
  ..$ : num  1 2 6 7 8 3
  ..$ : num  1 2 3 1 2 3 4 5 6 7 ...
  ..$ : num  1 2 3
  ..$ : num  1 1 4
>

On Fri, Jul 16, 2010 at 10:51 AM, Balpo <balpo at gmx.net> wrote:
>  Hello to all!
> I am new with R and I need your help.
> I'm trying to read a file which contests are similar to this:
> A    B    C    T    Lengths
> 1    4.0    0.0015258789    18    c(1,2,3)
> 1    1.0    0.0017166138    24    c(1,1,4)
>
> So all the columns are numeric values, except Lengths, which is supposed to
> be an variable length array of integers.
> How can I make R read them as arrays of integers? Or otherwise, convert the
> character array to an array of integers.
> When I read the file, I do it like this
> t1 = read.table(file=paste("./borrar.dat",sep=""), header=T,
> colClasses=c("numeric", "numeric", "numeric", "numeric", "array"))
> But the 5th column is treated as an array of characters, and when trying to
> convert it to another class of data, I either
> get two strings "c(1,2,3)" and "c(1,1,4)" or using a toRaw converter, I get
> the corresponding ASCII ¿? values.
> Should the input be modified in order to be able to read it as an array of
> integers?
>
> Thank you for your help.
> Balpo
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?