MATLAB: Creating a subset of a dataset array based on values in one of the variables

dataset arraysubset

Suppose I have a dataset array 8 x 3 arranged as such:
 Hospital   Floor  Beds
A           R3  10
A           T7  10
A           Z5  8
B           Q1  9
B           Q8  23
B           G2  13
C           I8  13
C           D5  15
What I want is a subset of this dataset array in which Hospital Floor is B, as shown below:
Hospital   Floor  Beds
B           Q1  9
B           Q8  23
B           G2  13
Any ideas? Thanks!

Best Answer

Similar to per isakson's suggestion, but with proper indexing on the "Hospital" column:
>> subset = your_ds_array( strcmp( 'B', your_ds_array.Hospital ), : );
Or, if you want to eliminate the strcmp which can be slow if your array is large and you do alot of these queries, convert the hospital column to a nominal array first:
>> your_ds_array.Hospital = nominal(your_ds_array.Hospital);
>> subset = your_ds_array( your_ds_array.Hospital == 'B', : );
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