I reformatted your data as a CSV, and read it into a table:
>> t = readtable('tmp5.csv','Format','%s%C%C%C%C','ReadRowNames',true)
t =
90×4 table
Country Artist Sport Colour
_____________ _________ __________ ______
id_1 Colombia Shakira Soccer Green
id_2 Colombia Metallica Rugby Yellow
id_3 Sweden Abba Ice hockey Blue
id_4 United States Metallica Baseball Red
id_5 United States ACDC Ice hockey Yellow
id_6 Colombia Shakira Soccer Green
id_7 Colombia ACDC Soccer Yellow
id_8 Colombia Shakira Rugby Blue
id_9 Colombia Shakira Soccer Red
id_10 Sweden Abba Ice hockey Blue
id_11 Australia ACDC Rugby Yellow
id_12 Australia ACDC Rugby Yellow
[snip]
Then count the number of rows within each artist/country combination. (This has the drawback that any combinations that are not present will not show up in the result. I think the crosstab function avoids that.):
>> tcounts = varfun(@(x) length(x), t,'GroupingVariables',{'Artist' 'Country'},'InputVariables',{})
tcounts =
16×3 table
Artist Country GroupCount
_________ _____________ __________
ACDC Australia 15
ACDC Colombia 3
ACDC Sweden 1
ACDC United States 4
Abba Australia 4
Abba Colombia 1
Abba Sweden 16
Abba United States 2
Metallica Australia 1
Metallica Colombia 5
Metallica Sweden 1
Metallica United States 17
Shakira Australia 1
Shakira Colombia 15
Shakira Sweden 3
Shakira United States 1
Depending on what you mneed, that might be your stopping point. If you want the actual cross-tabulation, you can unstack the counts by country, for each artist:
>> tcrosstab = unstack(tcounts,'GroupCount','Artist');
>> tcrosstab.Properties.RowNames = cellstr(tcrosstab.Country); tcrosstab.Country = [];
>> tcrosstab
tcrosstab =
4×4 table
ACDC Abba Metallica Shakira
____ ____ _________ _______
Australia 15 4 1 1
Colombia 3 1 5 15
Sweden 1 16 1 3
United States 4 2 17 1
This gets you a table, which provides nice named subscripting, but is not useful for further numeric calculations. Depending on what you need, you can take one more step:
>> tcrosstab.Variables
ans =
15 4 1 1
3 1 5 15
1 16 1 3
4 2 17 1
