MATLAB Answers

How to sort data (multiple rows into one)

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Nadine
Nadine on 15 Mar 2021
Commented: Nadine on 16 Mar 2021
I need to sort data from multiple rows in one row. We used multiple trials (= target_number) in an experiment and the software stored the target_type, number_picture, duration, cue_condition, current_cue_picture, etc. for each trial. I've colored below the data that belongs together to one trail:
I'm interested in the identification_button and identification_RT for each trial. So I guess the data must be sorted like:
Is there a way to sort it with MATLAB automatically?

Accepted Answer

Seth Furman
Seth Furman on 15 Mar 2021
This sounds like a good use for unstack.
For example, suppose we have the following table, consisting of 3 consecutive trials and the names "a", "b", "c" and "d".
t =
12×2 table
Name Value
____ _____
"a" 82
"b" 91
"c" 13
"d" 92
"a" 64
"b" 10
"c" 28
"d" 55
"a" 96
"b" 97
"c" 16
"d" 98
We can create a Trial variable for grouping as follows
trial = floor( (0:height(t)-1) / length(unique(t.Name)))' + 1;
>> t.Trial = trial
t =
12×3 table
Name Value Trial
____ _____ _____
"a" 82 1
"b" 91 1
"c" 13 1
"d" 92 1
"a" 64 2
"b" 10 2
"c" 28 2
"d" 55 2
"a" 96 3
"b" 97 3
"c" 16 3
"d" 98 3
and then unstack the Value variable using Name as our indicator variable and grouping the values by trial number
>> unstack(t,'Value','Name','GroupingVariables','Trial')
ans =
3×5 table
Trial a b c d
_____ __ __ __ __
1 82 91 13 92
2 64 10 28 55
3 96 97 16 98

More Answers (1)

Nadine
Nadine on 15 Mar 2021
Already answered it myself. =)
Extracted the values (right column, column 7) for each variable Name (column 6) and put all together in one table:
If there's an easier way -- just let me know!

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