Thank you Phil - I'll give this a try. I do have some empty rows, so I'll have
to deal with that eventually.
Dave
Sent via DROID X
-----Original message-----
From: Phil Spector <spec...@stat.berkeley.edu>
To: David Herzberg <dav...@wpspublish.com>
Cc: "r-help@r-project.org" <r-help@r-project.org>
Sent: Thu, Oct 28, 2010 23:39:34 GMT+00:00
Subject: Re: [R] Determining a basal correct count
David -
I *think*
apply(x,1,function(x)rle(x[which(x==1)[1]:length(x)])$lengths[1])
gives you what you want, but without a reproducible example it's
hard to say. It will fail if there are no 1s in a given row.
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spec...@stat.berkeley.edu
On Thu, 28 Oct 2010, David Herzberg wrote:
> Here's another interesting problem: if you recall I have a data frame
> (LCvars1) that consists of about 1500 cases (rows) of data from kids who took
> a test of listening comprehension. The columns are their scores (1 = correct,
> 0 = incorrect, . = missing) on 140 test items. The items are numbered
> sequentially and are ordered by increasing difficulty as you go from left to
> right across the columns.
>
> I used the following (thanks to Peter Ehlers for this solution):
>
> First1ItemNo <- as.vector(
> apply(
> LCvars1, 1, match, x=1
> ))
>
> to make R go through the columns from left to right and record into a vector
> the column number of the first '1' response for each case.
>
> Now, for each case (row), I want R to START with the column that contains the
> first '1' response, and continue to the right and count the number of
> consecutive columns containing '1' responses. At the next '0' or '.', I want
> R to record the count of consecutive '1's, and the skip to the next row and
> begin the process anew.
>
> Thanks in advance for your help,
>
> David S. Herzberg, Ph.D.
> Vice President, Research and Development
> Western Psychological Services
> 12031 Wilshire Blvd.
> Los Angeles, CA 90025-1251
> Phone: (310)478-2061 x144
> FAX: (310)478-7838
> email: dav...@wpspublish.com<mailto:dav...@wpspublish.com>
>
>
>
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>
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