# How To Assign Operator/Variables with a value

조회 수: 58(최근 30일)
Hi, I am currently working on a task of Linear Genetic Programming,
I have a question, how is the way to create the variable register and operator register in matlab?
I need to create that
1= +, 2= -, 3= *,4=/ and other operator
and variable register
1=x1, and so on.
I use ' ' and put them in matrix, but I cannot use them to calculation while I am evaluating the chromosome.
lets say I have A=[1 2 3 4], this means
X=2*4
(1 is X, and 3=*)
can anyone help me?

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### 채택된 답변

Walter Roberson 7 Oct 2020
functions = {@plus, @minus, @times, @rdivide};
Now you can take the character representing the operator, subtract '0' (the character for the digit 0), and use that to index functions to get the function handle of the operator to execute.
If you need different variables, then create a vector of zeros, and take the character representing the variable number, subtract '0' and use that to index the variables vector.

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### 추가 답변(1개)

Peter O 6 Oct 2020
I'm not familiar with LGP.
Consider a cell array to hold the chromosome?
C = {X, 2, @times, 4}
Using the operator definitions with function handles permits you to assign multiple and unknown operators. Alternatively, you can code them like you had 1=+, 2=-, etc and use an if/else on eval of the chromosome.
If permitted, I'd also suggest considering RPN notation to handle the arguments. A little cleaner/easier ordering.
C = {X, @times, 2, 4} --> Assign X @times(2,4)
Handles for 4 Fcn Basics: @plus, @minus, @times, @mrdivide

#### 댓글 수: 1

I tried put 1=+, 2=-, and so on. but it did not work
is it possible to use 1=@plus?

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