Jonas Walter
2013-Feb-25 13:38 UTC
[R] creating variable that codes for the match/mismatch between two other variables
Dear all,
I have got two vectors coding for a stimulus presented in the current trial
(mydat$Stimulus) and a prediction in the same trial (mydat$Prediciton),
respectively.
By applying an if-conditional I want to create a new vector that indicates if
there is a match between both vectors in the same trial. That is, if the
prediction equals the stimulus.
When I pick out some trials randomly, I get some trials with no match
(mydat$Stimulus[1] != mydat$Prediction[1]) as well as some trials with a match
(mydat$Stimulus[1] == mydat$Prediction[1]).
However, if I apply the following code, each trial is coded as a match. Why,
what do I wrong?
In some blocks, there was no prediction recorded. Therefore, I want those trials
to be labeled differently [that is, match = 7].
Coding-legend:
1 = match
0 = no match
7 = no prediction recorded
The code:
# create varialbe that codes match/mismatch of prediction vs. stimulus
mydat$match <- 0
for (i in seq_along(1:nrow(mydat))) {
# if there is a match, mydat$match[i] = 1 if (mydat$Stimulus[i] ==
mydat$Prediction[i]) {
mydat$match = 1
# the next to conditions refer to blocks without prediction recording.
Therefore, the corresponding trials are coded with mydat$match[i] = 7. }
else if (mydat$BlockOrder[i] == 1 & mydat$Block_nr[i] == 1) {
mydat$match = 7
} else if (mydat$BlockOrder[i] == 2 & mydat$Block_nr[i] == 4) {
mydat$match == 7
}
}
# The corresponding dataframe structure:
str(mydat)
'data.frame': 9302 obs. of 18 variables:
$ BlockOrder : int 1 1 1 1 1 1 1 1 1 1 ...
$ Block_nr : num 1 1 1 1 1 1 1 1 1 1 ...
$ Trial_nr : int 1 2 3 4 5 6 7 8 9 10 ...
$ PreSeq.Length : int 1 2 2 1 1 2 0 2 2 2 ...
$ PreSeq : int 21 12 21 20 20 12 0 21 22 11 ...
$ Sequence : int 121111 121212 121111 121111 112212 121221 121111
121111 122112 121111 ...
$ Category : int 2 1 3 2 1 1 3 3 1 3 ...
$ FixCross.Latency : int 1429 1043 1093 1297 1155 1449 1140 1396 1341 1427 ...
$ Stimulus : int 2 1 2 2 1 1 1 1 2 1 ...
$ RT : int 333 275 378 428 442 388 340 394 414 542 ...
$ RT.Button_pressed: int 2 1 2 2 1 1 1 1 2 1 ...
$ RT.Accuracy : int 1 1 1 1 1 1 1 1 1 1 ...
$ Prediction : int 0 0 0 0 0 0 0 0 0 0 ...
$ Confidence : int 0 0 0 0 0 0 0 0 0 0 ...
$ ITI : int 1053 1182 1467 1431 1103 1170 1232 1393 1356 1495 ...
$ Subject : num 4 4 4 4 4 4 4 4 4 4 ...
$ ITruns : num 0 0 0 1 0 1 2 3 0 0 ...
$ match : num 1 1 1 1 1 1 1 1 1 1 ...
# mydat$match, the new variable, only contains ones.
min(mydat$match)
[1] 1> max(mydat$match)
[1] 1
# example: row 1699: no match Stimulus - Prediction
mydat$Stimulus[1699] == mydat$Prediction[1699]
# [1] FALSE
# but:
mydat$match[1699]
# [1] 1
How can I get the right coding? Where is the mistake?
Thanks!
Best,
Jonas Walter
[[alternative HTML version deleted]]
PIKAL Petr
2013-Feb-25 14:53 UTC
[R] creating variable that codes for the match/mismatch between two other variables
Hi> -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r- > project.org] On Behalf Of Jonas Walter > Sent: Monday, February 25, 2013 2:38 PM > To: r-help at r-project.org > Subject: [R] creating variable that codes for the match/mismatch > between two other variables > > > > Dear all, > > I have got two vectors coding for a stimulus presented in the current > trial (mydat$Stimulus) and a prediction in the same trial > (mydat$Prediciton), respectively. > By applying an if-conditional I want to create a new vector that > indicates if there is a match between both vectors in the same trial. > That is, if the prediction equals the stimulus. > > When I pick out some trials randomly, I get some trials with no match > (mydat$Stimulus[1] != mydat$Prediction[1]) as well as some trials with > a match (mydat$Stimulus[1] == mydat$Prediction[1]). > > However, if I apply the following code, each trial is coded as a match. > Why, what do I wrong? > > In some blocks, there was no prediction recorded. Therefore, I want > those trials to be labeled differently [that is, match = 7]. > > Coding-legend: > > 1 = match > 0 = no match > 7 = no prediction recorded > > The code: > > # create varialbe that codes match/mismatch of prediction vs. stimulus > > mydat$match <- 0 > > for (i in seq_along(1:nrow(mydat))) { > # if there is a match, mydat$match[i] = 1 if > (mydat$Stimulus[i] == mydat$Prediction[i]) { > mydat$match = 1 > # the next to conditions refer to blocks without prediction recording. > Therefore, the corresponding trials are coded with mydat$match[i] = 7. > } else if (mydat$BlockOrder[i] == 1 & mydat$Block_nr[i] == 1) { > mydat$match = 7 > } else if (mydat$BlockOrder[i] == 2 & mydat$Block_nr[i] == 4) { > mydat$match == 7 > } > }Well, why so complicated? (mydat$Stimulus == mydat$Prediction)*1 gives you vector of 1 when there is match and 0 when there is no match. I do not understand your no prediction though. How is no prediction coded? If NA, the resulting vector will have NA in corresponding item too. Regards Petr> > # The corresponding dataframe structure: > > str(mydat) > 'data.frame': 9302 obs. of 18 variables: > $ BlockOrder : int 1 1 1 1 1 1 1 1 1 1 ... > $ Block_nr : num 1 1 1 1 1 1 1 1 1 1 ... > $ Trial_nr : int 1 2 3 4 5 6 7 8 9 10 ... > $ PreSeq.Length : int 1 2 2 1 1 2 0 2 2 2 ... > $ PreSeq : int 21 12 21 20 20 12 0 21 22 11 ... > $ Sequence : int 121111 121212 121111 121111 112212 121221 > 121111 121111 122112 121111 ... > $ Category : int 2 1 3 2 1 1 3 3 1 3 ... > $ FixCross.Latency : int 1429 1043 1093 1297 1155 1449 1140 1396 1341 > 1427 ... > $ Stimulus : int 2 1 2 2 1 1 1 1 2 1 ... > $ RT : int 333 275 378 428 442 388 340 394 414 542 ... > $ RT.Button_pressed: int 2 1 2 2 1 1 1 1 2 1 ... > $ RT.Accuracy : int 1 1 1 1 1 1 1 1 1 1 ... > $ Prediction : int 0 0 0 0 0 0 0 0 0 0 ... > $ Confidence : int 0 0 0 0 0 0 0 0 0 0 ... > $ ITI : int 1053 1182 1467 1431 1103 1170 1232 1393 1356 > 1495 ... > $ Subject : num 4 4 4 4 4 4 4 4 4 4 ... > $ ITruns : num 0 0 0 1 0 1 2 3 0 0 ... > $ match : num 1 1 1 1 1 1 1 1 1 1 ... > > # mydat$match, the new variable, only contains ones. > > min(mydat$match) > [1] 1 > > max(mydat$match) > [1] 1 > > # example: row 1699: no match Stimulus - Prediction > > mydat$Stimulus[1699] == mydat$Prediction[1699] # [1] FALSE > > # but: > > mydat$match[1699] > # [1] 1 > > How can I get the right coding? Where is the mistake? > > Thanks! > > Best, > Jonas Walter > > > [[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.