Count numbers for occurrences

I'm guessing at your variable names and their format... but assuming that UserID and Product are both numeric variables, you can use the nnz (number of nonzero) function to get a count.

For example, say you want the number of Product 2 that UserID 6 purchased:

count = nnz( (myTable.UserID == 6) & (myTable.Product == 2) )

You can, of course, extend this to different user IDs and product numbers as you see fit. I'd make this into a function:

function count = getProdCount(t,uid,prod)
% t = Table
% uid = User ID
% prod = Product number
      count = nnz( (t.UserID == uid) & (t.Product == prod) );
end

Then you can call it as follows:

count = getProdCount(myTable,6,2)

- Sebastian

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Panayiotis Christodoulou 2016-5-18

i created my own code based on my data using the first sentence

count = nnz( (myTable.UserID == 6) & (myTable.Product == 2) )

thanks

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Answer 2

Duncan Po 2016-5-17

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If you are using R2015b or later versions, you can use findgroups and splitapply:

% Set up a table with pretend data
userid  = [1; 1; 1; 1; 1; 2; 2; 2; 2; 2; 2; 3];
product = [1; 1; 2; 3; 3; 1; 2; 2; 2; 2; 2; 3];
T = table(userid,product);
% split into groups and compute counts
[g, T2] = findgroups(T);
T2.count = splitapply(@numel,T,g);  
% trim the table
T2 = T2(ismember(T2.product,[1 2]),:)

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Answer 3

the cyclist 2016-5-16

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Here is one way, generally using table functions to do everything.

% Set up a table with pretend data
userid  = [1; 1; 1; 1; 1; 2; 2; 2; 2; 2; 2; 3];
product = [1; 1; 2; 3; 3; 1; 2; 2; 2; 2; 2; 3];
T = table(userid,product);
% Find counts where product = 1 (and rename the resulting variable)
T1 = varfun(@(x)sum(x==1),T,'InputVariables','product','GroupingVariables','userid');
T1.Properties.VariableNames{'Fun_product'} = 'Product1'
% Find counts where product = 2 (and rename the resulting variable)
T2 = varfun(@(x)sum(x==2),T,'InputVariables','product','GroupingVariables','userid');
T2.Properties.VariableNames{'Fun_product'} = 'Product2'
% Join the results
T12 = join(T1,T2)