[R] Ignoring initial rows in a text file import

[David Winsemius]

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