Multiply/divided two tables

How would I mulyiply two tables togther. I have one table and I took two columns from the table and I want to multiply them togther. Also how would I divide as well thanks.

Answer 1

[Steven Lord]

The arithmetic operators aren't defined for table or timetable arrays, in part because they often contain data for which those arithmetic operators don't really make sense.

load patients
patients = table(LastName,Gender,Age,Height,Weight,Smoker,Systolic,Diastolic);
head(patients)

ans = 8x8 table
      LastName        Gender      Age    Height    Weight    Smoker    Systolic    Diastolic
    ____________    __________    ___    ______    ______    ______    ________    _________

    {'Smith'   }    {'Male'  }    38       71       176      true        124          93    
    {'Johnson' }    {'Male'  }    43       69       163      false       109          77    
    {'Williams'}    {'Female'}    38       64       131      false       125          83    
    {'Jones'   }    {'Female'}    40       67       133      false       117          75    
    {'Brown'   }    {'Female'}    49       64       119      false       122          80    
    {'Davis'   }    {'Female'}    46       68       142      false       121          70    
    {'Miller'  }    {'Female'}    33       64       142      true        130          88    
    {'Wilson'  }    {'Male'  }    40       68       180      false       115          82    

What should the variable LastName in patients2 in the example below contain? How about the variable Smoker?

%{
patients2 = 2*patients
%}

As Jon and KALYAN ACHARJYA said, you can operate on the variables in a table. One thing their posts did not show is that you don't have to store the results to a temporary variable then put them into a table. You can stick them directly back into the table.

patients.AgeNextYear = patients.Age + 1;
patients.WeightKG = patients.Weight/2.205;
patients.HeightM = patients.Height/39.37;
patients.BMI = patients.WeightKG./(patients.HeightM).^2;

% Extract just a few variables to display from patients
patients2 = patients(:, ["LastName", "Age", "AgeNextYear", "HeightM", "WeightKG", "BMI"]);
head(patients2)

ans = 8x6 table
      LastName      Age    AgeNextYear    HeightM    WeightKG     BMI  
    ____________    ___    ___________    _______    ________    ______

    {'Smith'   }    38         39         1.8034      79.819     24.542
    {'Johnson' }    43         44         1.7526      73.923     24.066
    {'Williams'}    38         39         1.6256       59.41     22.482
    {'Jones'   }    40         41         1.7018      60.317     20.827
    {'Brown'   }    49         50         1.6256      53.968     20.423
    {'Davis'   }    46         47         1.7272      64.399     21.587
    {'Miller'  }    33         34         1.6256      64.399      24.37
    {'Wilson'  }    40         41         1.7272      81.633     27.364

[Yogesh Bhambhwani]

Thanks

[Yogesh Bhambhwani]

Also do you know how to plot two tables

[Steven Lord]

Plotting isn't defined for table arrays for much the same reason that the arithmetic operators aren't. But just as with the arithmetic operators, you can index into the table and call the plot function on the retrieved data.

load patients
patients = table(LastName,Gender,Age,Height,Weight,Smoker,Systolic,Diastolic);
plot(patients.Height, patients.Weight, 'o')

Answer 2

[Jon]

% suppose you have a table T1 and T2 you could do something like

A = [T1.myColumnName1 T1.myColumnName2]
B = [T2.myColumnName3 T2.myColumnName4]
C = A.*B % assuming you want element by element multiplication
D = A./B % assuming you want element by element division

[KALYAN ACHARJYA]

Example:

data1=randi(20,[10,1]);
data2=randi(20,[10,1]);
table1=table(data1,data2)
data1=randi(10,[10,1]);
data2=randi(10,[10,1]);
table2=table(data1,data2)
% Multiple table 1,table2
data1=table1.data1.*table2.data1;
data2=table1.data2.*table2.data2;
result_mul_table=table(data1,data2)

[Yogesh Bhambhwani]

I am a little confused I only have in table and I want to mulyiply two of the columns in that one table togther so I have a variable with one of the columns and another variable with the other column I want to multiply with. and I also want to multpy the product of the two by a number and then divide all of that with another column from the same table where I got the other values.

[Jon]

Assuming as Steven Lord suggests that you want to add the new computed column in the same table following your verbal description:

T.newColumn = myNumericalValue*T.oneColumn.*T.anotherColumn./T.yetAnotherColumn

If you just want to have that as a vector you could assign the left hand side to your vector, v

v = myNumericalValue*T.oneColumn.*T.anotherColumn./T.yetAnotherColumn