八度，错误未定义变量，无法将数据数组识别为函数的输入

Question

all my variables are declared in my main script as you can see below:

DataArray.a = 1;
DataArray.b = 2;
d = 3;


DataArray = test1_2 (d, DataArray);

disp(DataArray);

The main script also works with some functions. A input of these functions is the data array which is declared in the main script:

function DataArray = test1_2 (d, DataArray )

g = DataArray.a;
h = DataArray.b;

DataArray.result = d * g* h;
endfunction

When I run the main script the following error occurs:

error: 'DataArray' undefined near line 3 column 5
error: called from test1_2 at line 3 column 3

If i type in for example the DataArray.a, octave knows that it is declared and gives out "1".

How can I use the same data array in my main script as well as in my function?

Answer 1

When you say

DataArray = test1_2 (DataArray);

Your test1_2 function is called with one argument. Inside the function:

function DataArray = test1_2 (d, e, f, DataArray )

only the first argument, d , is defined. The other arguments remain undefined. Note that the names of the arguments inside the function are totally unrelated to the names of variables you use to call the function. That is, inside the function, the variable d contains whatever DataArray contains outside the function, not what is inside the variable d outside the function. Octave does not try to match up variable names like this.

So, given that your function needs 4 input arguments, you should call it as this:

DataArray = test1_2(d, e, f, DataArray )

I suggest you read the excellent tutorials from MATLAB, for example these about writing functions . As you know, Octave mostly mimics the MATLAB syntax, so the MATLAB tutorials are also a good way to get started with Octave.