MATLAB Answers

How to make a list of appearance

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R G
R G on 25 Sep 2020
Commented: Ameer Hamza on 25 Sep 2020
Hi guys,
I am having some lists of animal which some animal appear many time in many list. So I want to count the appearance of animal and show how many times it appear, then save it to excel file
the data after saving in excel shoulbe be like this
name , count
a 1
b 3
c 2
I have think about 2d- char array but it seems Matlab does not support it.

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Accepted Answer

Ameer Hamza
Ameer Hamza on 25 Sep 2020
Edited: Ameer Hamza on 25 Sep 2020
Use findgrpups() and histcounts(). Something like this
names = ["cat" "dog" "cat" "cat" "dog"];
[n, unique_names] = findgroups(names);
freq = accumarray(n(:), 1);
T = table(unique_names(:), freq(:));
Result
>> T
T =
2×2 table
Var1 Var2
_____ ____
"cat" 3
"dog" 2
Write to excel file
writetable(T, 'filename.xlsx')
In R2019a and later, following will also work
names = ["cat" "dog" "cat" "cat" "dog"];
[freq, unique_names] = groupcounts(names(:));
T = table(unique_names(:), freq(:));

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Ameer Hamza
Ameer Hamza on 25 Sep 2020
Ah! I didn't try to run the code after changing. Try the updated code now. I have now used another function.
R G
R G on 25 Sep 2020
Thank you, it works well now!!!
Ameer Hamza
Ameer Hamza on 25 Sep 2020
I am glad to be of help!

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More Answers (2)

KSSV
KSSV on 25 Sep 2020
Let str be your list of animals.
xbins = unique(str);
[counts,centres] = hist(str,xbins);
R = [centres counts']

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Steven Lord
Steven Lord on 25 Sep 2020
histcounts and histogram can handle categorical arrays.
names = ["cat" "dog" "cat" "cat" "dog"];
animals = categorical(names);
[counts, types] = histcounts(animals);
results = table(types.', counts.', 'VariableNames', ["animal", "population"])

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