Re: [R] Conditional looping over a set of variables in R
Peter, thanks for this elegant solution that works well and handles the empty
cases. However, the vector it returns includes both the row (case) numbers and
the target result (number of column of first 1). How can I strip out the row
numbers and leave only the target result.
Regards,
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
-Original Message-
From: Peter Ehlers [mailto:ehl...@ucalgary.ca]
Sent: Tuesday, October 26, 2010 9:23 AM
To: David Herzberg
Cc: Petr PIKAL; r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
I would still recommend
vector_of_column_number - apply(yourdata, 1, match, x=1)
as the simplest way if you only want the number of the column that has the
first 1 or 1 (the call works as is for both numeric and character data). Rows
which have no 1s will return a value of NA.
Anything wrong with it?
-Peter Ehlers
On 2010-10-26 07:50, David Herzberg wrote:
Thank you - I will try this solution as well.
Sent via DROID X
-Original message-
From: Petr PIKALpetr.pi...@precheza.cz
To: David Herzbergdav...@wpspublish.com
Cc: Adrienne Woottenamwoo...@ncsu.edu,
r-help@r-project.orgr-help@r-project.org
Sent: Tue, Oct 26, 2010 06:43:09 GMT+00:00
Subject: Re: [R] Conditional looping over a set of variables in R
Hi
r-help-boun...@r-project.org napsal dne 25.10.2010 20:41:55:
Adrienne, there's one glitch when I implement your solution below.
When
the
loop encounters a case with no data at all (that is, all 140 item
responses
are missing), it aborts and prints this error message: ERROR:
argument
is
of length zero.
I wonder if there's a logical condition I could add that would enable
R
to
skip these empty cases and continue executing on the next case that
contains data.
Thanks, Dave
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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com]
On
Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns
and
1500
rows, but the same or similar notation can be applied to data frames
in
R. If
I understand correctly, you are looking for the first response
(column)
where
you got a value of 1. I'm assuming also that since your missing
values
are
characters then your two numeric values are also characters. keeping
all this
in mind, try something like this.
If you really only want to know which column in each row has first
occurrence of 1 (or any other value) you can get rid of looping and
use other R capabilities.
set.seed(111)
mat-matrix(sample(1:3, 20, replace=T),5,4) mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,]3121
[3,]2213
[4,]2211
[5,]2112
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
2 3 4 5
2 3 3 2
mat[2, ]-NA
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,] NA NA NA NA
[3,]2213
[4,]2211
[5,]2112
and this approach smoothly works with NA values too
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
3 4 5
3 3 2
You can then use modify such output as you have info about columns and
rows. I am sure there are other maybe better options, e.g.
lll-as.list(as.data.frame(t(mat)))
unlist(lapply(lll, function(x) min(which(x==1
V1 V2 V3 V4 V5
Inf Inf 3 3 2
Regards
Petr
first = c() # your extra variable which will eventually contain the
first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct
answer,
and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David
Herzbergdav...@wpspublish.com mailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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 want R
Re: [R] Conditional looping over a set of variables in R
On 2010-10-27 06:21, David Herzberg wrote:
Peter, thanks for this elegant solution that works well and handles the empty cases.
However, the vector it returns includes both the row (case) numbers and the target result
(number of column of first 1). How can I strip out the row numbers and leave
only the target result.
Use unname(x) or as.vector(x) on the result.
-Peter Ehlers
Regards,
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
-Original Message-
From: Peter Ehlers [mailto:ehl...@ucalgary.ca]
Sent: Tuesday, October 26, 2010 9:23 AM
To: David Herzberg
Cc: Petr PIKAL; r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
I would still recommend
vector_of_column_number- apply(yourdata, 1, match, x=1)
as the simplest way if you only want the number of the column that has the first 1 or
1 (the call works as is for both numeric and character data). Rows which have
no 1s will return a value of NA.
Anything wrong with it?
-Peter Ehlers
On 2010-10-26 07:50, David Herzberg wrote:
Thank you - I will try this solution as well.
Sent via DROID X
-Original message-
From: Petr PIKALpetr.pi...@precheza.cz
To: David Herzbergdav...@wpspublish.com
Cc: Adrienne Woottenamwoo...@ncsu.edu,
r-help@r-project.orgr-help@r-project.org
Sent: Tue, Oct 26, 2010 06:43:09 GMT+00:00
Subject: Re: [R] Conditional looping over a set of variables in R
Hi
r-help-boun...@r-project.org napsal dne 25.10.2010 20:41:55:
Adrienne, there's one glitch when I implement your solution below.
When
the
loop encounters a case with no data at all (that is, all 140 item
responses
are missing), it aborts and prints this error message: ERROR:
argument
is
of length zero.
I wonder if there's a logical condition I could add that would enable
R
to
skip these empty cases and continue executing on the next case that
contains data.
Thanks, Dave
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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com]
On
Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns
and
1500
rows, but the same or similar notation can be applied to data frames
in
R. If
I understand correctly, you are looking for the first response
(column)
where
you got a value of 1. I'm assuming also that since your missing
values
are
characters then your two numeric values are also characters. keeping
all this
in mind, try something like this.
If you really only want to know which column in each row has first
occurrence of 1 (or any other value) you can get rid of looping and
use other R capabilities.
set.seed(111)
mat-matrix(sample(1:3, 20, replace=T),5,4) mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,]3121
[3,]2213
[4,]2211
[5,]2112
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
2 3 4 5
2 3 3 2
mat[2, ]-NA
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,] NA NA NA NA
[3,]2213
[4,]2211
[5,]2112
and this approach smoothly works with NA values too
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
3 4 5
3 3 2
You can then use modify such output as you have info about columns and
rows. I am sure there are other maybe better options, e.g.
lll-as.list(as.data.frame(t(mat)))
unlist(lapply(lll, function(x) min(which(x==1
V1 V2 V3 V4 V5
Inf Inf 3 3 2
Regards
Petr
first = c() # your extra variable which will eventually contain the
first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct
answer,
and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David
Herzbergdav...@wpspublish.com mailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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
Re: [R] Conditional looping over a set of variables in R
Hi
r-help-boun...@r-project.org napsal dne 25.10.2010 20:41:55:
Adrienne, there's one glitch when I implement your solution below. When
the
loop encounters a case with no data at all (that is, all 140 item
responses
are missing), it aborts and prints this error message: ERROR: argument
is
of length zero.
I wonder if there's a logical condition I could add that would enable R
to
skip these empty cases and continue executing on the next case that
contains data.
Thanks, Dave
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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com] On
Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns and
1500
rows, but the same or similar notation can be applied to data frames in
R. If
I understand correctly, you are looking for the first response (column)
where
you got a value of 1. I'm assuming also that since your missing values
are
characters then your two numeric values are also characters. keeping
all this
in mind, try something like this.
If you really only want to know which column in each row has first
occurrence of 1 (or any other value) you can get rid of looping and use
other R capabilities.
set.seed(111)
mat-matrix(sample(1:3, 20, replace=T),5,4)
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,]3121
[3,]2213
[4,]2211
[5,]2112
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
2 3 4 5
2 3 3 2
mat[2, ]-NA
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,] NA NA NA NA
[3,]2213
[4,]2211
[5,]2112
and this approach smoothly works with NA values too
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
3 4 5
3 3 2
You can then use modify such output as you have info about columns and
rows. I am sure there are other maybe better options, e.g.
lll-as.list(as.data.frame(t(mat)))
unlist(lapply(lll, function(x) min(which(x==1
V1 V2 V3 V4 V5
Inf Inf 3 3 2
Regards
Petr
first = c() # your extra variable which will eventually contain the
first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct answer,
and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David Herzberg dav...@wpspublish.com
mailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and find the first correct
response
for each case. Because of basal and ceiling rules, many cases have
missing
data on many items before the first correct response appears.
For each case, I want R to evaluate the item responses sequentially
starting
with item 1. If the score is 0 or missing, proceed to the next item and
evaluate it. If the score is 1, stop the operation for that case, record
the
item number of that first correct response in a new variable, proceed to
the
next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO
IF, as
follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS LCfirst1 = 0.
#i IS
AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH ELEMENT
OF
THE VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES THE FIRST
ELEMENT OF
THE VECTOR (THAT IS, THE FIRST OF THE 140 ITEM RESPONSES). AS THE LOOP
RUNS
AND #i INCREASES, SUBSEQUENT VECTOR ELELMENTS ARE EVALUATED. THE do if
STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH THE VECTOR UNTIL A
'1
Re: [R] Conditional looping over a set of variables in R
Thank you - I will try this solution as well.
Sent via DROID X
-Original message-
From: Petr PIKAL petr.pi...@precheza.cz
To: David Herzberg dav...@wpspublish.com
Cc: Adrienne Wootten amwoo...@ncsu.edu, r-help@r-project.org
r-help@r-project.org
Sent: Tue, Oct 26, 2010 06:43:09 GMT+00:00
Subject: Re: [R] Conditional looping over a set of variables in R
Hi
r-help-boun...@r-project.org napsal dne 25.10.2010 20:41:55:
Adrienne, there's one glitch when I implement your solution below. When
the
loop encounters a case with no data at all (that is, all 140 item
responses
are missing), it aborts and prints this error message: ERROR: argument
is
of length zero.
I wonder if there's a logical condition I could add that would enable R
to
skip these empty cases and continue executing on the next case that
contains data.
Thanks, Dave
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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com] On
Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns and
1500
rows, but the same or similar notation can be applied to data frames in
R. If
I understand correctly, you are looking for the first response (column)
where
you got a value of 1. I'm assuming also that since your missing values
are
characters then your two numeric values are also characters. keeping
all this
in mind, try something like this.
If you really only want to know which column in each row has first
occurrence of 1 (or any other value) you can get rid of looping and use
other R capabilities.
set.seed(111)
mat-matrix(sample(1:3, 20, replace=T),5,4)
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,]3121
[3,]2213
[4,]2211
[5,]2112
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
2 3 4 5
2 3 3 2
mat[2, ]-NA
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,] NA NA NA NA
[3,]2213
[4,]2211
[5,]2112
and this approach smoothly works with NA values too
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
3 4 5
3 3 2
You can then use modify such output as you have info about columns and
rows. I am sure there are other maybe better options, e.g.
lll-as.list(as.data.frame(t(mat)))
unlist(lapply(lll, function(x) min(which(x==1
V1 V2 V3 V4 V5
Inf Inf 3 3 2
Regards
Petr
first = c() # your extra variable which will eventually contain the
first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct answer,
and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David Herzberg dav...@wpspublish.com
mailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and find the first correct
response
for each case. Because of basal and ceiling rules, many cases have
missing
data on many items before the first correct response appears.
For each case, I want R to evaluate the item responses sequentially
starting
with item 1. If the score is 0 or missing, proceed to the next item and
evaluate it. If the score is 1, stop the operation for that case, record
the
item number of that first correct response in a new variable, proceed to
the
next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO
IF, as
follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS LCfirst1 = 0.
#i IS
AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH ELEMENT
OF
THE VE
[[alternative
Re: [R] Conditional looping over a set of variables in R
I would still recommend
vector_of_column_number - apply(yourdata, 1, match, x=1)
as the simplest way if you only want the number of the
column that has the first 1 or 1 (the call works as is
for both numeric and character data). Rows which have no
1s will return a value of NA.
Anything wrong with it?
-Peter Ehlers
On 2010-10-26 07:50, David Herzberg wrote:
Thank you - I will try this solution as well.
Sent via DROID X
-Original message-
From: Petr PIKALpetr.pi...@precheza.cz
To: David Herzbergdav...@wpspublish.com
Cc: Adrienne Woottenamwoo...@ncsu.edu,
r-help@r-project.orgr-help@r-project.org
Sent: Tue, Oct 26, 2010 06:43:09 GMT+00:00
Subject: Re: [R] Conditional looping over a set of variables in R
Hi
r-help-boun...@r-project.org napsal dne 25.10.2010 20:41:55:
Adrienne, there's one glitch when I implement your solution below. When
the
loop encounters a case with no data at all (that is, all 140 item
responses
are missing), it aborts and prints this error message: ERROR: argument
is
of length zero.
I wonder if there's a logical condition I could add that would enable R
to
skip these empty cases and continue executing on the next case that
contains data.
Thanks, Dave
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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com] On
Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns and
1500
rows, but the same or similar notation can be applied to data frames in
R. If
I understand correctly, you are looking for the first response (column)
where
you got a value of 1. I'm assuming also that since your missing values
are
characters then your two numeric values are also characters. keeping
all this
in mind, try something like this.
If you really only want to know which column in each row has first
occurrence of 1 (or any other value) you can get rid of looping and use
other R capabilities.
set.seed(111)
mat-matrix(sample(1:3, 20, replace=T),5,4)
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,]3121
[3,]2213
[4,]2211
[5,]2112
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
2 3 4 5
2 3 3 2
mat[2, ]-NA
mat
[,1] [,2] [,3] [,4]
[1,]2222
[2,] NA NA NA NA
[3,]2213
[4,]2211
[5,]2112
and this approach smoothly works with NA values too
mat.w-which(mat==1, arr.ind=T)
tapply(mat.w[,2], mat.w[,1], min)
3 4 5
3 3 2
You can then use modify such output as you have info about columns and
rows. I am sure there are other maybe better options, e.g.
lll-as.list(as.data.frame(t(mat)))
unlist(lapply(lll, function(x) min(which(x==1
V1 V2 V3 V4 V5
Inf Inf 3 3 2
Regards
Petr
first = c() # your extra variable which will eventually contain the
first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct answer,
and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David Herzbergdav...@wpspublish.com
mailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and find the first correct
response
for each case. Because of basal and ceiling rules, many cases have
missing
data on many items before the first correct response appears.
For each case, I want R to evaluate the item responses sequentially
starting
with item 1. If the score is 0 or missing, proceed to the next item and
evaluate it. If the score is 1, stop the operation for that case, record
the
item number of that first correct response in a new variable, proceed to
the
next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO
IF, as
follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD
Re: [R] Conditional looping over a set of variables in R
Adrienne, there's one glitch when I implement your solution below. When the
loop encounters a case with no data at all (that is, all 140 item responses are
missing), it aborts and prints this error message: ERROR: argument is of
length zero.
I wonder if there's a logical condition I could add that would enable R to skip
these empty cases and continue executing on the next case that contains data.
Thanks, Dave
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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com] On Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns and 1500
rows, but the same or similar notation can be applied to data frames in R. If
I understand correctly, you are looking for the first response (column) where
you got a value of 1. I'm assuming also that since your missing values are
characters then your two numeric values are also characters. keeping all this
in mind, try something like this.
first = c() # your extra variable which will eventually contain the first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct answer, and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David Herzberg
dav...@wpspublish.commailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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
want R to go through the data and find the first correct response for each
case. Because of basal and ceiling rules, many cases have missing data on many
items before the first correct response appears.
For each case, I want R to evaluate the item responses sequentially starting
with item 1. If the score is 0 or missing, proceed to the next item and
evaluate it. If the score is 1, stop the operation for that case, record the
item number of that first correct response in a new variable, proceed to the
next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO IF, as
follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT RESPONSE,
SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS LCfirst1 = 0. #i IS
AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH ELEMENT OF THE
VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES THE FIRST ELEMENT OF THE
VECTOR (THAT IS, THE FIRST OF THE 140 ITEM RESPONSES). AS THE LOOP RUNS AND #i
INCREASES, SUBSEQUENT VECTOR ELELMENTS ARE EVALUATED. THE do if STATEMENT
RETAINS CONTROL AND KEEPS LOOPING THROUGH THE VECTOR UNTIL A '1' IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT STATEMENT, WHICH
RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'.
+ comp x(#i) = 99.
* AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE VALUE OF
LCfirst1 TO THE CURRENT INDEX VALUE, THUS CAPTURING THE ITEM NUMBER OF THE
FIRST CORRECT RESPONSE FOR THAT CASE. CHANGING THE VALUE OF LCfirst1 ALSO CAUSE
S THE LOOP TO STOP EXECUTING FOR THAT CASE, AND THE PROGRAM MOVES TO THE NEXT
CASE AND RESTARTS THE LOOP.
+ comp LCfirst1 = #i.
+ end if.
end loop.
exe.
After several hours of trying to translate this procedure to R, I'm stumped. I
played around with creating a list to hold the item responses variables
(analogous to 'vector' in SPSS), but when I tried to use the list in an R
procedure, I kept getting a warning along the lines of 'the list contains 1
element, only the first element will be used'. So perhaps a list is not the
appropriate class to 'hold' these variables?
It seems that some nested arrangement of 'for' 'while' and/or 'lapply' will
allow me to recreate the operation described above? How do I set up the
indexing operation analogous to 'loop #i' in SPSS?
Any help is appreciated, and I'm happy
Re: [R] Conditional looping over a set of variables in R
Adrienne - this solves the problem nicely. Thanks 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
From: wootten.adrie...@gmail.com [mailto:wootten.adrie...@gmail.com] On Behalf
Of Adrienne Wootten
Sent: Friday, October 22, 2010 9:09 AM
To: David Herzberg
Cc: r-help@r-project.org
Subject: Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns and 1500
rows, but the same or similar notation can be applied to data frames in R. If
I understand correctly, you are looking for the first response (column) where
you got a value of 1. I'm assuming also that since your missing values are
characters then your two numeric values are also characters. keeping all this
in mind, try something like this.
first = c() # your extra variable which will eventually contain the first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct answer, and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David Herzberg
dav...@wpspublish.commailto:dav...@wpspublish.com wrote:
Here's the problem I'm trying to solve in R: I have a data frame 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
want R to go through the data and find the first correct response for each
case. Because of basal and ceiling rules, many cases have missing data on many
items before the first correct response appears.
For each case, I want R to evaluate the item responses sequentially starting
with item 1. If the score is 0 or missing, proceed to the next item and
evaluate it. If the score is 1, stop the operation for that case, record the
item number of that first correct response in a new variable, proceed to the
next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO IF, as
follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT RESPONSE,
SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS LCfirst1 = 0. #i IS
AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH ELEMENT OF THE
VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES THE FIRST ELEMENT OF THE
VECTOR (THAT IS, THE FIRST OF THE 140 ITEM RESPONSES). AS THE LOOP RUNS AND #i
INCREASES, SUBSEQUENT VECTOR ELELMENTS ARE EVALUATED. THE do if STATEMENT
RETAINS CONTROL AND KEEPS LOOPING THROUGH THE VECTOR UNTIL A '1' IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT STATEMENT, WHICH
RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'.
+ comp x(#i) = 99.
* AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE VALUE OF
LCfirst1 TO THE CURRENT INDEX VALUE, THUS CAPTURING THE ITEM NUMBER OF THE
FIRST CORRECT RESPONSE FOR THAT CASE. CHANGING THE VALUE OF LCfirst1 ALSO CAUSE
S THE LOOP TO STOP EXECUTING FOR THAT CASE, AND THE PROGRAM MOVES TO THE NEXT
CASE AND RESTARTS THE LOOP.
+ comp LCfirst1 = #i.
+ end if.
end loop.
exe.
After several hours of trying to translate this procedure to R, I'm stumped. I
played around with creating a list to hold the item responses variables
(analogous to 'vector' in SPSS), but when I tried to use the list in an R
procedure, I kept getting a warning along the lines of 'the list contains 1
element, only the first element will be used'. So perhaps a list is not the
appropriate class to 'hold' these variables?
It seems that some nested arrangement of 'for' 'while' and/or 'lapply' will
allow me to recreate the operation described above? How do I set up the
indexing operation analogous to 'loop #i' in SPSS?
Any help is appreciated, and I'm happy to provide more information if needed.
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.commailto:dav...@wpspublish.com
[[alternative HTML version deleted
Re: [R] Conditional looping over a set of variables in R
This won't be as quick as Bill's elegant solution, but it's a one-liner:
apply(d, 1, function(x), match(1, x))
See ?match.
-Peter Ehlers
On 2010-10-22 10:36, David Herzberg wrote:
Bill, thanks so much for this. I'll get a chance to test it later today, and
will post the outcome.
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
-Original Message-
From: William Dunlap [mailto:wdun...@tibco.com]
Sent: Friday, October 22, 2010 9:52 AM
To: David Herzberg; r-help@r-project.org
Subject: RE: [R] Conditional looping over a set of variables in R
You were a bit vague about the format of your data.
I'm assuming all columns were numeric and the entries are one of 0, 1, and NA
(missing value). I made a little function to generate random data of that
format for testing purposes:
makeData- function (nrow = 1500, ncol = 140, pMissing = 0.1) {
# pMissing if proportion of missing values
m- matrix(sample(c(1, 0), size = nrow * ncol, replace = TRUE),
nrow, ncol)
m[runif(nrow * ncol) pMissing]- NA
data.frame(m)
}
E.g.,
set.seed(168)
d- makeData(15,3)
d
X1 X2 X3
1 1 1 1
2 0 0 NA
3 0 1 0
4 0 0 NA
5 0 1 1
6 0 0 NA
7 1 0 0
8 0 1 1
9 0 0 1
10 1 1 NA
11 0 0 1
12 0 0 0
13 NA NA NA
14 0 0 0
15 1 0 0
I think the following function does what you want.
The algorithm is pretty similar to what you showed.
columnOfFirstOne- function(data) {
# col will be return value, one entry per row of data.
# Fill it with NA's: NA in output will mean there were no 1's in row
col- rep(as.integer(NA), nrow(data))
for (j in seq_len(ncol(data))) { # loop over columns
# For each entry in 'col', if it has not been set yet
# and this entry the j'th column of data is 1 (and not
missing)
# then set to the column number.
col[is.na(col) !is.na(data[, j]) data[, j] == 1]- j
}
col # return this from function
}
With the above data we get
columnOfFirstOne(d)
[1] 1 NA 2 NA 2 NA 1 2 3 1 3 NA NA NA 1
It seems quick enough for a dataset of your size
dd- makeData(nrow=1500, ncol=140)
system.time(columnOfFirstOne(dd)) # time in seconds
user system elapsed
0.080.000.08
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-Original Message-
From: r-help-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of David Herzberg
Sent: Friday, October 22, 2010 8:34 AM
To: r-help@r-project.org
Subject: [R] Conditional looping over a set of variables in R
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and
find the first correct response for each case. Because of basal and
ceiling rules, many cases have missing data on many items before the
first correct response appears.
For each case, I want R to evaluate the item responses sequentially
starting with item 1. If the score is 0 or missing, proceed to the
next item and evaluate it. If the score is 1, stop the operation for
that case, record the item number of that first correct response in a
new variable, proceed to the next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO
IF, as follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS
LCfirst1 = 0. #i IS AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME
THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH
ELEMENT OF THE VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES
THE FIRST ELEMENT OF THE VECTOR (THAT IS, THE FIRST OF THE 140 ITEM
RESPONSES). AS THE LOOP RUNS AND #i INCREASES, SUBSEQUENT VECTOR
ELELMENTS ARE EVALUATED.
THE do if STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH THE
VECTOR UNTIL A '1' IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT STATEMENT,
WHICH RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'.
+ comp x(#i) = 99.
* AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE
VALUE OF LCfirst1 TO THE CURRENT INDEX VALUE
Re: [R] Conditional looping over a set of variables in R
Whoops, got an extra comma in there somehow; should be:
apply(d, 1, function(x) match(1, x))
-Peter Ehlers
On 2010-10-24 08:17, Peter Ehlers wrote:
This won't be as quick as Bill's elegant solution, but it's a one-liner:
apply(d, 1, function(x), match(1, x))
See ?match.
-Peter Ehlers
On 2010-10-22 10:36, David Herzberg wrote:
Bill, thanks so much for this. I'll get a chance to test it later today, and
will post the outcome.
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
-Original Message-
From: William Dunlap [mailto:wdun...@tibco.com]
Sent: Friday, October 22, 2010 9:52 AM
To: David Herzberg; r-help@r-project.org
Subject: RE: [R] Conditional looping over a set of variables in R
You were a bit vague about the format of your data.
I'm assuming all columns were numeric and the entries are one of 0, 1, and NA
(missing value). I made a little function to generate random data of that
format for testing purposes:
makeData- function (nrow = 1500, ncol = 140, pMissing = 0.1) {
# pMissing if proportion of missing values
m- matrix(sample(c(1, 0), size = nrow * ncol, replace = TRUE),
nrow, ncol)
m[runif(nrow * ncol) pMissing]- NA
data.frame(m)
}
E.g.,
set.seed(168)
d- makeData(15,3)
d
X1 X2 X3
1 1 1 1
2 0 0 NA
3 0 1 0
4 0 0 NA
5 0 1 1
6 0 0 NA
7 1 0 0
8 0 1 1
9 0 0 1
10 1 1 NA
11 0 0 1
12 0 0 0
13 NA NA NA
14 0 0 0
15 1 0 0
I think the following function does what you want.
The algorithm is pretty similar to what you showed.
columnOfFirstOne- function(data) {
# col will be return value, one entry per row of data.
# Fill it with NA's: NA in output will mean there were no 1's in row
col- rep(as.integer(NA), nrow(data))
for (j in seq_len(ncol(data))) { # loop over columns
# For each entry in 'col', if it has not been set yet
# and this entry the j'th column of data is 1 (and not
missing)
# then set to the column number.
col[is.na(col) !is.na(data[, j]) data[, j] == 1]- j
}
col # return this from function
}
With the above data we get
columnOfFirstOne(d)
[1] 1 NA 2 NA 2 NA 1 2 3 1 3 NA NA NA 1
It seems quick enough for a dataset of your size
dd- makeData(nrow=1500, ncol=140)
system.time(columnOfFirstOne(dd)) # time in seconds
user system elapsed
0.080.000.08
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-Original Message-
From: r-help-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of David Herzberg
Sent: Friday, October 22, 2010 8:34 AM
To: r-help@r-project.org
Subject: [R] Conditional looping over a set of variables in R
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and
find the first correct response for each case. Because of basal and
ceiling rules, many cases have missing data on many items before the
first correct response appears.
For each case, I want R to evaluate the item responses sequentially
starting with item 1. If the score is 0 or missing, proceed to the
next item and evaluate it. If the score is 1, stop the operation for
that case, record the item number of that first correct response in a
new variable, proceed to the next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO
IF, as follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS
LCfirst1 = 0. #i IS AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME
THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH
ELEMENT OF THE VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES
THE FIRST ELEMENT OF THE VECTOR (THAT IS, THE FIRST OF THE 140 ITEM
RESPONSES). AS THE LOOP RUNS AND #i INCREASES, SUBSEQUENT VECTOR
ELELMENTS ARE EVALUATED.
THE do if STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH THE
VECTOR UNTIL A '1' IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES
Re: [R] Conditional looping over a set of variables in R
On Sun, Oct 24, 2010 at 2:54 PM, Peter Ehlers ehl...@ucalgary.ca wrote: Whoops, got an extra comma in there somehow; should be: apply(d, 1, function(x) match(1, x)) A slight variation on this would be: apply(d, 1, match, x = 1) -- Statistics Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com __ 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.
[R] Conditional looping over a set of variables in R
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and find the first correct response for each case. Because of basal and ceiling rules, many cases have missing data on many items before the first correct response appears. For each case, I want R to evaluate the item responses sequentially starting with item 1. If the score is 0 or missing, proceed to the next item and evaluate it. If the score is 1, stop the operation for that case, record the item number of that first correct response in a new variable, proceed to the next case, and restart the operation. In SPSS, this operation would be carried out with LOOP, VECTOR, and DO IF, as follows (assuming the data set is already loaded): * DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT RESPONSE, SET IT EQUAL TO 0. numeric LCfirst1. comp LCfirst1 = 0 * DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES. vector x=LC1a_score to LC140a_score. * SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS LCfirst1 = 0. #i IS AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME THE LOOP RUNS. loop #i=1 to 140 if (LCfirst1 = 0). * SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH ELEMENT OF THE VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES THE FIRST ELEMENT OF THE VECTOR (THAT IS, THE FIRST OF THE 140 ITEM RESPONSES). AS THE LOOP RUNS AND #i INCREASES, SUBSEQUENT VECTOR ELELMENTS ARE EVALUATED. THE do if STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH THE VECTOR UNTIL A '1' IS ENCOUNTERED. + do if x(#i) = 1. * WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'. + comp x(#i) = 99. * AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE VALUE OF LCfirst1 TO THE CURRENT INDEX VALUE, THUS CAPTURING THE ITEM NUMBER OF THE FIRST CORRECT RESPONSE FOR THAT CASE. CHANGING THE VALUE OF LCfirst1 ALSO CAUSE S THE LOOP TO STOP EXECUTING FOR THAT CASE, AND THE PROGRAM MOVES TO THE NEXT CASE AND RESTARTS THE LOOP. + comp LCfirst1 = #i. + end if. end loop. exe. After several hours of trying to translate this procedure to R, I'm stumped. I played around with creating a list to hold the item responses variables (analogous to 'vector' in SPSS), but when I tried to use the list in an R procedure, I kept getting a warning along the lines of 'the list contains 1 element, only the first element will be used'. So perhaps a list is not the appropriate class to 'hold' these variables? It seems that some nested arrangement of 'for' 'while' and/or 'lapply' will allow me to recreate the operation described above? How do I set up the indexing operation analogous to 'loop #i' in SPSS? Any help is appreciated, and I'm happy to provide more information if needed. 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 [[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.
Re: [R] Conditional looping over a set of variables in R
David,
here I'm referring to your data as testmat, a matrix of 140 columns and 1500
rows, but the same or similar notation can be applied to data frames in R.
If I understand correctly, you are looking for the first response (column)
where you got a value of 1. I'm assuming also that since your missing
values are characters then your two numeric values are also characters.
keeping all this in mind, try something like this.
first = c() # your extra variable which will eventually contain the first
correct response for each case
for(i in 1:nrow(testmat)){
c = 1
while( c=ncol(testmat) | testmat[i,c] != 1 ){
if( testmat[i,c] == 1){
first[i] = c
break # will exit the while loop once it finds the first correct answer, and
then jump to the next case
} else {
c=c+1 # procede to the next column if not
}
}
}
Hope this helps you out a bit.
Adrienne Wootten
NCSU
On Fri, Oct 22, 2010 at 11:33 AM, David Herzberg dav...@wpspublish.comwrote:
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and find the first
correct response for each case. Because of basal and ceiling rules, many
cases have missing data on many items before the first correct response
appears.
For each case, I want R to evaluate the item responses sequentially
starting with item 1. If the score is 0 or missing, proceed to the next item
and evaluate it. If the score is 1, stop the operation for that case, record
the item number of that first correct response in a new variable, proceed to
the next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO IF,
as follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS LCfirst1 = 0. #i
IS AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH ELEMENT OF
THE VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES THE FIRST ELEMENT
OF THE VECTOR (THAT IS, THE FIRST OF THE 140 ITEM RESPONSES). AS THE LOOP
RUNS AND #i INCREASES, SUBSEQUENT VECTOR ELELMENTS ARE EVALUATED. THE do if
STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH THE VECTOR UNTIL A '1'
IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT STATEMENT, WHICH
RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'.
+ comp x(#i) = 99.
* AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE VALUE OF
LCfirst1 TO THE CURRENT INDEX VALUE, THUS CAPTURING THE ITEM NUMBER OF THE
FIRST CORRECT RESPONSE FOR THAT CASE. CHANGING THE VALUE OF LCfirst1 ALSO
CAUSE S THE LOOP TO STOP EXECUTING FOR THAT CASE, AND THE PROGRAM MOVES TO
THE NEXT CASE AND RESTARTS THE LOOP.
+ comp LCfirst1 = #i.
+ end if.
end loop.
exe.
After several hours of trying to translate this procedure to R, I'm
stumped. I played around with creating a list to hold the item responses
variables (analogous to 'vector' in SPSS), but when I tried to use the list
in an R procedure, I kept getting a warning along the lines of 'the list
contains 1 element, only the first element will be used'. So perhaps a
list is not the appropriate class to 'hold' these variables?
It seems that some nested arrangement of 'for' 'while' and/or 'lapply' will
allow me to recreate the operation described above? How do I set up the
indexing operation analogous to 'loop #i' in SPSS?
Any help is appreciated, and I'm happy to provide more information if
needed.
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
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R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible
Re: [R] Conditional looping over a set of variables in R
You were a bit vague about the format of your data.
I'm assuming all columns were numeric and the entries
are one of 0, 1, and NA (missing value). I made a
little function to generate random data of that format
for testing purposes:
makeData - function (nrow = 1500, ncol = 140, pMissing = 0.1)
{
# pMissing if proportion of missing values
m - matrix(sample(c(1, 0), size = nrow * ncol, replace = TRUE),
nrow, ncol)
m[runif(nrow * ncol) pMissing] - NA
data.frame(m)
}
E.g.,
set.seed(168)
d - makeData(15,3)
d
X1 X2 X3
1 1 1 1
2 0 0 NA
3 0 1 0
4 0 0 NA
5 0 1 1
6 0 0 NA
7 1 0 0
8 0 1 1
9 0 0 1
10 1 1 NA
11 0 0 1
12 0 0 0
13 NA NA NA
14 0 0 0
15 1 0 0
I think the following function does what you want.
The algorithm is pretty similar to what you showed.
columnOfFirstOne - function(data) {
# col will be return value, one entry per row of data.
# Fill it with NA's: NA in output will mean there were no 1's in
row
col - rep(as.integer(NA), nrow(data))
for (j in seq_len(ncol(data))) { # loop over columns
# For each entry in 'col', if it has not been set yet
# and this entry the j'th column of data is 1 (and not
missing)
# then set to the column number.
col[is.na(col) !is.na(data[, j]) data[, j] == 1] - j
}
col # return this from function
}
With the above data we get
columnOfFirstOne(d)
[1] 1 NA 2 NA 2 NA 1 2 3 1 3 NA NA NA 1
It seems quick enough for a dataset of your size
dd - makeData(nrow=1500, ncol=140)
system.time(columnOfFirstOne(dd)) # time in seconds
user system elapsed
0.080.000.08
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-Original Message-
From: r-help-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of David Herzberg
Sent: Friday, October 22, 2010 8:34 AM
To: r-help@r-project.org
Subject: [R] Conditional looping over a set of variables in R
Here's the problem I'm trying to solve in R: I have a data
frame 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 want R to go through the data and
find the first correct response for each case. Because of
basal and ceiling rules, many cases have missing data on many
items before the first correct response appears.
For each case, I want R to evaluate the item responses
sequentially starting with item 1. If the score is 0 or
missing, proceed to the next item and evaluate it. If the
score is 1, stop the operation for that case, record the item
number of that first correct response in a new variable,
proceed to the next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP,
VECTOR, and DO IF, as follows (assuming the data set is
already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST
CORRECT RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS
LCfirst1 = 0. #i IS AN INDEX VARIABLE THAT INCREASES BY 1
EACH TIME THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR
EACH ELEMENT OF THE VECTOR. THUS, WHEN #i = 1, THE
EXPRESSION EVALUATES THE FIRST ELEMENT OF THE VECTOR (THAT
IS, THE FIRST OF THE 140 ITEM RESPONSES). AS THE LOOP RUNS
AND #i INCREASES, SUBSEQUENT VECTOR ELELMENTS ARE EVALUATED.
THE do if STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH
THE VECTOR UNTIL A '1' IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT
STATEMENT, WHICH RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'.
+ comp x(#i) = 99.
* AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH
RECODES THE VALUE OF LCfirst1 TO THE CURRENT INDEX VALUE,
THUS CAPTURING THE ITEM NUMBER OF THE FIRST CORRECT RESPONSE
FOR THAT CASE. CHANGING THE VALUE OF LCfirst1 ALSO CAUSE S
THE LOOP TO STOP EXECUTING FOR THAT CASE, AND THE PROGRAM
MOVES TO THE NEXT CASE AND RESTARTS THE LOOP.
+ comp LCfirst1 = #i.
+ end if.
end loop.
exe.
After several hours of trying to translate this procedure to
R, I'm stumped. I played around with creating a list to hold
the item responses variables (analogous to 'vector' in SPSS),
but when I tried to use the list in an R procedure, I kept
getting a warning along the lines of 'the list contains 1
element, only the first element will be used'. So perhaps a
list is not the appropriate
Re: [R] Conditional looping over a set of variables in R
Bill, thanks so much for this. I'll get a chance to test it later today, and
will post the outcome.
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
-Original Message-
From: William Dunlap [mailto:wdun...@tibco.com]
Sent: Friday, October 22, 2010 9:52 AM
To: David Herzberg; r-help@r-project.org
Subject: RE: [R] Conditional looping over a set of variables in R
You were a bit vague about the format of your data.
I'm assuming all columns were numeric and the entries are one of 0, 1, and NA
(missing value). I made a little function to generate random data of that
format for testing purposes:
makeData - function (nrow = 1500, ncol = 140, pMissing = 0.1) {
# pMissing if proportion of missing values
m - matrix(sample(c(1, 0), size = nrow * ncol, replace = TRUE),
nrow, ncol)
m[runif(nrow * ncol) pMissing] - NA
data.frame(m)
}
E.g.,
set.seed(168)
d - makeData(15,3)
d
X1 X2 X3
1 1 1 1
2 0 0 NA
3 0 1 0
4 0 0 NA
5 0 1 1
6 0 0 NA
7 1 0 0
8 0 1 1
9 0 0 1
10 1 1 NA
11 0 0 1
12 0 0 0
13 NA NA NA
14 0 0 0
15 1 0 0
I think the following function does what you want.
The algorithm is pretty similar to what you showed.
columnOfFirstOne - function(data) {
# col will be return value, one entry per row of data.
# Fill it with NA's: NA in output will mean there were no 1's in row
col - rep(as.integer(NA), nrow(data))
for (j in seq_len(ncol(data))) { # loop over columns
# For each entry in 'col', if it has not been set yet
# and this entry the j'th column of data is 1 (and not
missing)
# then set to the column number.
col[is.na(col) !is.na(data[, j]) data[, j] == 1] - j
}
col # return this from function
}
With the above data we get
columnOfFirstOne(d)
[1] 1 NA 2 NA 2 NA 1 2 3 1 3 NA NA NA 1
It seems quick enough for a dataset of your size
dd - makeData(nrow=1500, ncol=140)
system.time(columnOfFirstOne(dd)) # time in seconds
user system elapsed
0.080.000.08
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-Original Message-
From: r-help-boun...@r-project.org
[mailto:r-help-boun...@r-project.org] On Behalf Of David Herzberg
Sent: Friday, October 22, 2010 8:34 AM
To: r-help@r-project.org
Subject: [R] Conditional looping over a set of variables in R
Here's the problem I'm trying to solve in R: I have a data frame 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 want R to go through the data and
find the first correct response for each case. Because of basal and
ceiling rules, many cases have missing data on many items before the
first correct response appears.
For each case, I want R to evaluate the item responses sequentially
starting with item 1. If the score is 0 or missing, proceed to the
next item and evaluate it. If the score is 1, stop the operation for
that case, record the item number of that first correct response in a
new variable, proceed to the next case, and restart the operation.
In SPSS, this operation would be carried out with LOOP, VECTOR, and DO
IF, as follows (assuming the data set is already loaded):
* DECLARE A NEW VARIABLE TO HOLD THE ITEM NUMBER OF THE FIRST CORRECT
RESPONSE, SET IT EQUAL TO 0.
numeric LCfirst1.
comp LCfirst1 = 0
* DECLARE A VECTOR TO HOLD THE 140 ITEM RESPONSE VARIABLES.
vector x=LC1a_score to LC140a_score.
* SET UP A LOOP THAT WILL RUN FROM 1 TO 140, AS LONG AS
LCfirst1 = 0. #i IS AN INDEX VARIABLE THAT INCREASES BY 1 EACH TIME
THE LOOP RUNS.
loop #i=1 to 140 if (LCfirst1 = 0).
* SET UP A CONDITIONAL TRANSFORMATION THAT IS EVALUATED FOR EACH
ELEMENT OF THE VECTOR. THUS, WHEN #i = 1, THE EXPRESSION EVALUATES
THE FIRST ELEMENT OF THE VECTOR (THAT IS, THE FIRST OF THE 140 ITEM
RESPONSES). AS THE LOOP RUNS AND #i INCREASES, SUBSEQUENT VECTOR
ELELMENTS ARE EVALUATED.
THE do if STATEMENT RETAINS CONTROL AND KEEPS LOOPING THROUGH THE
VECTOR UNTIL A '1' IS ENCOUNTERED.
+ do if x(#i) = 1.
* WHEN A '1' IS ENCOUNTERED, CONTROL PASSES TO THE NEXT STATEMENT,
WHICH RECODES THE VALUE OF THAT VECTOR ELEMENT TO '99'.
+ comp x(#i) = 99.
* AND THEN CONTROL PASSES TO THE NEXT STATEMENT, WHICH RECODES THE
VALUE OF LCfirst1 TO THE CURRENT INDEX VALUE, THUS CAPTURING THE ITEM
NUMBER OF THE FIRST CORRECT RESPONSE FOR THAT CASE. CHANGING THE VALUE
OF LCfirst1 ALSO CAUSE S THE LOOP TO STOP EXECUTING
