How to create a loop function for a set of parameters from a file to define each parameters as variables

I want to simplify my code by creating a loop function (for or switch). The data is given from a file (parameters) and I input my variable for each cell of different rows from the parameter file.

Please help me on how to implement this. Thank you.

xmin = parameters(1);

xmax = parameters(2);

ymin = parameters(3);

ymax = parameters(4);

dx = parameters(5);

gamma = parameters(6);

threshold = parameters(7);

Npos = parameters(8); Npos_1 = parameters(9:10);

Npos_2 = parameters(11:12);

Npos_3 = parameters(13:14);

Npos_4 = parameters(15:16);

[Rena Berman]

(Answers Dev) Restored Edits

Answer 1

[Guillaume]

In my opinion, the best thing would be change the way your read that file so that it's read directly into the variables (or better a table or structure) that you want instead of that paramaters array.

As it is, this may simplify your code slightly:

parameters = mat2cell(parameters, 1, [1 1 1 1 1 1 1 1 2 2 2 2]);  %asumming that paramters is a 1x16 row vector
[xmin, xmax, ymin, ymax, dx, gamma, threshold, Npos, Npos_1, Npos_2, Npos_3, NPos_4] = parameters{:};

[Rachel Ng]

Hmm, i did it but it looks better, however, I wanted to simplify it to a simpler version (such as putting it in a loop)

[Guillaume]

The only way you could use a loop would be with eval. This would make the code slower, harder to debug and certainly not simpler.

[Stephen23]

"I wanted to simplify it to a simpler version (such as putting it in a loop)"

Putting it into a loop would require magically creating variable names, which would make your code slower, buggier, harder to debug, and more obfuscated. Read the link in my answer to know why.

Answer 2

[Stephen23]

Dynamically creating variable names is not recommended. Read this to know why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Instead you can easily use a table, or generate fieldnames of a structure:

>> P = randi(99,1,16) % fake 1x16 data.
P =
   87    6   86   48   15   10   52   54   15   35   10   20   33   58   34   42
>> F = {'xmin','xmax','ymin','ymax','dx','gamma','threshold','Npos','Npos_1','Npos_2','Npos_3','Npos_4'};
>> S = cell2struct(mat2cell(P,1,[ones(1,8),1+ones(1,4)]),F,2)

This gives a structure S with the following fields:

    xmin =  87
    xmax =  6
    ymin =  86
    ymax =  48
    dx =  15
    gamma =  10
    threshold =  52
    Npos =  54
    Npos_1 =
       15   35
    Npos_2 =
       10   20
    Npos_3 =
       33   58
    Npos_4 =
       34   42

Answer 3

[pirpyn]

Since you seems to have a constant array and not a cell one, look at the deal function.

[Y1, Y2, Y3] = deal(X)

[Guillaume]

deal is rarely necessary. See its doc.

Your particular example would simply copy all of X into Y1, Y2 and Y3.