MATLAB: Match cell array of strings to table row names

match datamatch stringsMATLABtable

I have a table T1 of unique row names and corresponding weights (size is around 7000 rows)
T1:
row name WEIGHT
raining -1.3
house 3.5
happy 5
etc… (7000 rows)
I have a smaller (~100 row) cell array CA1 of strings, some of which appear in T1, some of which don't. Strings can be repeated in CA1.
CA1:
house
my
feet
raining
raining
etc… (100 rows)
I want all the matches between CA1 and T1 and, for these matches, to return a sum of the weights.
In the example above the output would be: 3.5+0+0-1.3-1.3 = 0.9 (since 'my', and 'feet' don't appear in T1 (hence the zeros) but 'house' and 'raining' do – with 'raining' appearing twice)
I can't make CA1 a table, since the row names wouldn't be unique. If a string appears n times in CA1 i want to have that weight added n times to my final sum.
I've checked the documentation, read a number on answers on this forum, but can't find how to do this. Using strcmp would seem to require an ugly and time consuming loop. I would appreciate any help. Thanks

Best Answer

First I create fake data (in the future, it would be helpful for you to provide this). Then we'll use ismember() to match the row numbers. The variable "weightSum" is the sum of selected weights. 
T1 = table([-1.3; 3.5; 5; 1; 2; 3; 4], 'VariableNames', {'Weight'}, 'RowNames', {'raining', 'house', 'happy', 'town', 'city', 'country', 'zip'}); 
CA1 = {'house'; 'my'; 'feet'; 'raining'; 'raining'; 'mousepad'}; 
% find rows numbers in T1 that match strings in CA1
[~, rowNum] = ismember(CA1, T1.Properties.RowNames);
% Add the weights of selected rows
rowNum(rowNum==0) = [];  %Remove 0s
weightSum = sum(T1.Weight(rowNum))
weightSum =
          0.9
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