Count how many times a number is repeated in a certain row of an array
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Nathaniel Werner
am 20 Jul. 2018
Verschoben: DGM
am 20 Jul. 2024 um 18:18
Please consider the array
A = [1;1;1;2;2;2;2;2;3;3;4;4;4;4;4;4;4;5;5;5;5];
I would like to determine how many times each number repeats.
For 1, it repeats three times. For 2, it repeats five times, and so on.
If there is other data in columns to the left of the array A that does not follow the same repeating pattern, can I still count how many times each number in a certain column is repeated?
2 Kommentare
Adam
am 20 Jul. 2018
doc histcounts
would be one way of doing it, depending on how many unique values you are likely to have, though however many there are you could use that many bins.
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Aquatris
am 20 Jul. 2018
Here is a code;
A = [1;1;1;2;2;2;2;2;3;3;4;4;4;4;4;4;4;5;5;5;5];
c = unique(A); % the unique values in the A (1,2,3,4,5)
for i = 1:length(c)
counts(i,1) = sum(A==c(i)); % number of times each unique value is repeated
end
% c(1) is repated count(1) times
16 Kommentare
Aquatris
am 5 Mai 2020
From the above example, the code can be (for relatively newer versions of Matlab;
d = c(counts<4);
where d has the value that appear less than 4 times in the A vector. Alternatively;
I = find(counts<4); % find indices where counts variable elements are less than 4
d=c(I);
PEDRO ALEXANDRE Fernandes
am 4 Mär. 2022
Hi. I have a similar problem. if i have a multidimensional array of the style 7 X 10
9 5 2 1 5 3 3
1 8 3 1 7 4 3
1 3 1 1 8 6 4
1 3 1 6 4 2 1
2 1 6 3 2 2 1
2 3 1 1 7 5 4
1 1 4 2 1 8 6
Columns 8 through 10
2 2 5
2 2 6
4 2 4
2 9 7
1 9 1
2 1 5
5 4 5
and I intend to count the number of times each digit appears per line.
Example: on line 1
1 -> 1
2 -> 3
3 -> 2
..
and then the same in the following lines. Any idea?
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