How to determine number of patients in the category

I am trying to determine how many patients fall into each BMI class and each blood pressure class. Like how many patients are "Normal", how many are "Overweight", etc. and how many have normal bp or high bp, etc. Here is the table I have formulated. It is named data_table. I am stuck on how to count the patients.

Answer 1

[Voss]

data_table = table([1;2;3;4;5;6],[24;26;25;28;27;26],["Underweight";"Optimal";"Obese";"Obese";"Obese";"Optimal"],["Low";"Normal";"Normal";"Pre Hypertension";"Stage 1 Hypertension";"Normal"],'VariableNames',{'ID','Age','BMI Class','Blood Pressure Class'})

data_table = 6x4 table
    ID    Age      BMI Class       Blood Pressure Class 
    __    ___    _____________    ______________________

    1     24     "Underweight"    "Low"                 
    2     26     "Optimal"        "Normal"              
    3     25     "Obese"          "Normal"              
    4     28     "Obese"          "Pre Hypertension"    
    5     27     "Obese"          "Stage 1 Hypertension"
    6     26     "Optimal"        "Normal"              

result = groupcounts(data_table,{'BMI Class','Blood Pressure Class'})

result = 5x4 table
      BMI Class       Blood Pressure Class     GroupCount    Percent
    _____________    ______________________    __________    _______

    "Obese"          "Normal"                      1         16.667 
    "Obese"          "Pre Hypertension"            1         16.667 
    "Obese"          "Stage 1 Hypertension"        1         16.667 
    "Optimal"        "Normal"                      2         33.333 
    "Underweight"    "Low"                         1         16.667 

Reference:

https://www.mathworks.com/help/matlab/ref/double.groupcounts.html

These may also be useful:

https://www.mathworks.com/help/matlab/ref/double.groupsummary.html

https://www.mathworks.com/help/matlab/ref/findgroups.html

https://www.mathworks.com/help/matlab/ref/splitapply.html

Answer 2

[Star Strider]

Use the accumarray function.

Try something like this —

imshow(imread('Screenshot 202....55.14 PM.png'))

BMIC = ["Underweight","Optimal","Obese"];
T = table(Size =[10,1], VariableTypes={'string'}, VariableNames={'BMI Class'});

T.('BMI Class') = BMIC(randi(3,10,1)).'

T = 10x1 table
      BMI Class  
    _____________

    "Obese"      
    "Underweight"
    "Underweight"
    "Obese"      
    "Optimal"    
    "Underweight"
    "Optimal"    
    "Obese"      
    "Optimal"    
    "Obese"      

[Cu,~,idx] = unique(T.('BMI Class'))

Cu = 3x1 string array
    "Obese"
    "Optimal"
    "Underweight"

idx = 10×1

1 3 3 1 2 3 2 1 2 1

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Tally = accumarray(idx, ones(size(idx)))

Tally = 3×1

4 3 3

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Result = table(Cu,Tally)

Result = 3x2 table
         Cu          Tally
    _____________    _____

    "Obese"            4  
    "Optimal"          3  
    "Underweight"      3  

.