[R] Ignoring initial rows in a text file import

[jim holtman]

This is the case where '\t' is the tab character; '\\t' would give you
the backslash followed by 't' which is not what you want.

On Mon, May 31, 2010 at 8:19 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On May 31, 2010, at 8:14 PM, jim holtman wrote:
>
>> try this:
>>
>> input  <- readLines("yourfile.txt")
>> # determine start
>> start <- grep("\tBegin Main\t", input)[1]  # first line if many
>
> Puzzled. I thought backslashes in grepping patterns needed to be doubled? I
> guess not.
>
> --
> David.
>
>> if (length(start) == 1 && (start > 1)){
>>   input <- tail(input, -(start - 1))  # delete heading lines
>> }
>> # find lines you want to delete
>> breaks <- grep("\tBreak\t", input)
>> if (length(breaks) > 0){
>>   input <- input[-breaks]
>> }
>> # now read in your data
>> real_input <- read.table(textConnection(input), header=TRUE)
>> closeAllConnections()
>>
>>
>>
>> On Mon, May 31, 2010 at 7:51 PM, Kevin Burnham <kburnham at gmail.com> wrote:
>>>
>>> I am trying to import a series of text files generated by stimulus
>>> presentation software.  The problem that I am having is that the number
>>> of
>>> rows I need to skip is not fixed (depending on subject's pretest
>>> behavior)
>>> nor is the first row of the data I want always the same (the stimuli were
>>> presented in random order).  So I need to bring in the .txt file (using
>>> readLines?), look for the row containing the text "Begin Main" (see exact
>>> row below) and start reading data to a table from that point.
>>>
>>>  [13] "Main Group\t1000\tBegin Main\tBegin Main\tBegin Main\t\t
>>> \tPressed\t(any response)\tC\t25860\t\t\t\t\t"
>>>
>>> I would also like it to ignore the row:
>>> [173] "Main Group\t1000\tBreak\tBreak\
>>> tpause3\t\t \tPressed\t(any response)\tC\t47610\t\t\t\t\t"
>>>
>>> which will always be the same number of rows after the "Begin Main" row.
>>>
>>> Thanks,
>>> Kevin Burnham
>>>
>>>       [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> 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.
>>>
>>
>>
>>
>> --
>> Jim Holtman
>> Cincinnati, OH
>> +1 513 646 9390
>>
>> What is the problem that you are trying to solve?
>>
>> ______________________________________________
>> 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.
>
> David Winsemius, MD
> West Hartford, CT
>
>



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

What is the problem that you are trying to solve?