Count numbers for occurrences
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Panayiotis Christodoulou
le 16 Mai 2016
Modifié(e) : the cyclist
le 18 Mai 2016
Hi there,
I have a table
UserID, Market, Geo, Price, Product
I want to count for each userID how many times he bought product = 1 and how many times product=2
Final Dataset UserID, Product1, Product2
Thanks, Pan
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Sebastian Castro
le 16 Mai 2016
Modifié(e) : Sebastian Castro
le 16 Mai 2016
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
Plus de réponses (2)
Duncan Po
le 17 Mai 2016
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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the cyclist
le 16 Mai 2016
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)
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