Matching two columns from an imported table to find the corresponding value in the 5th column.

I have a 401 x 12 table that was imported from excel into matlab. I want a function that returns a value from the 5th column when I give two values from the first two columns.

[Sebastian Daneli]

You need to specify your question. Can you give an example?

[Samuel Ofosu-Yeboah]

Alright. Sure.

The table has headings as Temperature, Pressure, Density, Internal energy, and Enthalpy as shown below. I want a function that takes a particular temperature and pressure to return the corresponding Enthalpy. Lets say, in the function I put 360 as temperature and 175.5 as density and it returns 2608 as enthalpy.

Hope this is much clearer. Thanks

Answer 1

[Enrico Gambini]

One method to extract what you want could be

    temp=input("Insert temperature: \n"); %here you insert the parameters in the command window
    
    %Otherwise you can do manually from the code
    temp=360; %you can change it
    
    

Then you can create your function code file

    function enthalpy=find_enthalpy(temp)
    idx=find((Table.Temperature(:)==temp); %i called "Table" your table from excel
    enthalpy=Table.Enthalpy(idx);
    fprintf("The enthalpy is :",enthalpy); %not necessary
    end

From your script, or directly from command window you can call the function

   enthalpy=find_enthalpy(temp)

Let me know if works

[Samuel Ofosu-Yeboah]

It is not running the above function .

Error- The function find_enthalpy might be unused

[Enrico Gambini]

Ya, I made a mistake, try now, I edited

[Samuel Ofosu-Yeboah]

New Error: Operands to the logical and (&&) and or (||) operators must be convertible to logical scalar values.

[Enrico Gambini]

If the pressure-temperature relation is univocal you can insert only the temperature. I edited

[Samuel Ofosu-Yeboah]

It worked perfectly!!

You have been so helpful!

Thank you for your time.