[R] read.table input array

Balpo balpo at gmx.net
Sat Oct 23 05:40:18 CEST 2010


Hello Jim

How can I ensure this reading it from the file?
The thing is, I cannot use the textConnection(), because the real file 
has millions of rows.

Thank you,

Balpo

On 22/10/10 21:34, jim holtman wrote:
> You need to make sure that your data is read in a characters and not factors:
>
>> x<- read.table(textConnection("ktot attractors pctstatesinattractors t lengths
> + 1.0 2.0 3.8146973E-4 17 c(2,2)
> + 1.0 1.0 5.722046E-4 28 c(2)
> + 1.0 2.0 9.536743E-4 18 c(2,2)
> + 1.0 1.0 0.0010490417 14 c(1)"), as.is = TRUE, header = TRUE)
>> closeAllConnections()
>> str(x)
> 'data.frame':   4 obs. of  5 variables:
>   $ ktot                 : num  1 1 1 1
>   $ attractors           : num  2 1 2 1
>   $ pctstatesinattractors: num  0.000381 0.000572 0.000954 0.001049
>   $ t                    : int  17 28 18 14
>   $ lengths              : chr  "c(2,2)" "c(2)" "c(2,2)" "c(1)"
>> x
>    ktot attractors pctstatesinattractors  t lengths
> 1    1          2          0.0003814697 17  c(2,2)
> 2    1          1          0.0005722046 28    c(2)
> 3    1          2          0.0009536743 18  c(2,2)
> 4    1          1          0.0010490417 14    c(1)
>> x$varList<- lapply(x$lengths, function(a) mean(eval(parse(text=a))))
>> x
>    ktot attractors pctstatesinattractors  t lengths varList
> 1    1          2          0.0003814697 17  c(2,2)       2
> 2    1          1          0.0005722046 28    c(2)       2
> 3    1          2          0.0009536743 18  c(2,2)       2
> 4    1          1          0.0010490417 14    c(1)       1
>
> On Fri, Oct 22, 2010 at 10:19 PM, Balpo<balpo at gmx.net>  wrote:
>> 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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