[R] read.table input array

[Balpo]

Hello again Jim (and everyone)
I am having a weird problem here with the same parsing thing.
For example, for the first row I have the following 5 columns.

1.0    2.0        3.8146973E-4        17    c(2,2)

I need to convert that c(2,2) into a list and get its mean, in this 
particular case mean=2. My program does:

t1 <- read.table(file="file.dat", header=T, colClasses=c("numeric", 
"numeric", "numeric", "numeric", "factor"))
t1$lengthz <- lapply(t1$lengths, function(a) eval(parse(text=a)))#As Jim 
thought me
t1$avglen <- as.vector(mode="numeric", lapply(t1$lengthz, function(i) 
mean(i)))

but the 6th column is strangely getting 780 instead of 2.
This solution used to work! :-(
Do you have any idea about what is going on?

I attach file.dat.

Thank you for your support.

Balpo


On 19/07/10 16:38, Balpo wrote:
>  Thank you a lot, Jim.
> Issue solved.
>
> Balpo
>
> On 16/07/10 11:27, jim holtman wrote:
>> 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
>>>
>>> ______________________________________________
>>> 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.
>>>
>>
>>
>
> ______________________________________________
> 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.
>
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