David -
I think changing
apply(x,1,function(x)rle(x[which(x==1)[1]:length(x)])$lengths[1])
to
apply(x,1,function(x)if(!any(x==1)) 0 else
rle(x[which(x==1)[1]:length(x)])$lengths[1])
solves the problem.
- Phil
On Thu, 28 Oct 2010, David Herzberg wrote:
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>
>
>
>
> [[alternative HTML version deleted]]
>
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