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: davidh@wpspublish.com<mailto:davidh@wpspublish.com> [[alternative HTML version deleted]]
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
spector at 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: davidh at wpspublish.com<mailto:davidh at wpspublish.com>
>
>
>
> [[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.
>
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 <spector@stat.berkeley.edu>
To: David Herzberg <davidh@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
spector@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: davidh@wpspublish.com<mailto:davidh@wpspublish.com>
>
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@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.
>
[[alternative HTML version deleted]]