Assign values to an array based on an if statement from a larger array

Question

Mathieu 2024-2-9

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https://ww2.mathworks.cn/matlabcentral/answers/2080421-assign-values-to-an-array-based-on-an-if-statement-from-a-larger-array

编辑： Fangjun Jiang 2024-2-12

Hi,

I have an 20 elements array (uint8) in which some elements can be '0' and I want to retrieve the first 8 values that are not '0' and assign them to another array (uint8).

I am constrained to using only slcilib blocks and submodules so the sorting option is not usable.

So far I have done something like this

However, it seems that the for loop never ends and I have to manually stop the model using ctrl + C.

Does anyone have an idea about this issue?

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Fangjun Jiang 2024-2-12

编辑：Fangjun Jiang 2024-2-12

I would use the MATLAB Function block. On the other hand, I don't think you are using the For Iterator block correctly. Take a look at the doc and example model.

Mathieu 2024-2-12

在 MATLAB Online 中打开

First of all, indeed, I was not using the for iterator as it should..

Then, I tried using the MATLAB function block, however the same problem is persisting which is how can I index my output array as it should only contain the first 8 values (that are not '0') of my input array?

At first I tried to do a for loop to go through my input array, then test the value with an if statement but I cannot think of a way to index the value to the output array without a for loop which is fully looping every time it is called (thus ovewritting previously stored elements).

I know that I am missing something but cannot say what, is there any way you can help me with that?

Down below is what I come up with:

inputArray = [0 1 0 3 0 5 0 7 0 9 0 11 0 13 0 15 0 17 0 19];
outputArray = [0 0 0 0 0 0 0 0];
for i=1:1:length(inputArray)
    if inputArray(i) > 0
        
        for j=1:1:j<8
            outputArray(j) = inputArray(i);
        end
    end
end
Warning: Colon operands must be real scalars.

The expected output for the above code should be:

outputArray = [1 3 5 7 9 11 13 15]

but instead I am having an empty array.

Thanks,

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Answer 1

Fangjun Jiang 2024-2-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2080421-assign-values-to-an-array-based-on-an-if-statement-from-a-larger-array#answer_1407196

编辑：Fangjun Jiang 2024-2-12

在 MATLAB Online 中打开

inputArray = [0 1 0 3 0 5 0 7 0 9 0 11 0 13 0 15 0 17 0 19 0 0 20 0 0 21];
index=(inputArray~=0);
tempData=inputArray(index);
outputArray=tempData(1:8)
outputArray = 1×8
     1     3     5     7     9    11    13    15