Question: How do I make the result of Result_Eva_GB_X2[3] := [] is [0]?

I have attached the problem here. I need to say sorry, because I did not provide the whole code. So, automatically It will be error if you execute it.

If you see the attachement, you will see "Result_Eva_GB_X2[3] := []". It makes a problem if I want to make comparison. So I want the result of "Result_Eva_GB_X2[3] := []" is [0].

Actually the result of Result_Eva_GB_X2[3] := [] is complex number, because I did not want the complex I made select(x->is(0<x<1)....) to eliminate the complex number and negative result. So the question is How do I make the result of Result_Eva_GB_X2[3] := [] is [0]?

I have tried to add "Selection Statement (if)" (If the result is Undefined ([]) then Result_Eva_GB_X2[3] := [0]) But it can not work. Or maybe the selection statement that I made was wrong.

Please Help me. Thank You very much

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