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# How to subtract from a vector array and, if the answer is lees than 0, have it return a value of 0

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Brett Baxter on 15 Sep 2020
Edited: John D'Errico on 15 Sep 2020
I'm trying to subtract a number from a specific value in a vector. Then, if the answer is less than 0, I want it to return the answer with it being rounded to 0.
this is what I meam
%example%
x = [1 2 3]
x(1)-2
%the result would look like this%
x =
-1 2 3
%but I want it to look like this%
x =
0 2 3
How do I do this without using conditionals?

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### Answers (2)

David Hill on 15 Sep 2020
x=[1 2 3];
x=x-2;
x(x<0)=0;

#### 2 Comments

Brett Baxter on 15 Sep 2020
Thank you, but now I need the function to tell me by how much it goes under if and when it does. I essentially need to write a function like this:
x=[1, 2 3]
y= 2
x(1) - y
if x(1)<0
totalsubtracted = y +x(1)
else
totalsubtracted = x(1)-y
end
But without conditionals. How do I do this?
David Hill on 15 Sep 2020
x=[1 2 3];
amountbelowzero=zeros(size(x));
x=x-2;
amountbelowzero(x<0)=abs(x(x<0));
x(x<0)=0;

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John D'Errico on 15 Sep 2020
Edited: John D'Errico on 15 Sep 2020
Simple. No need to test anything either. Just use the max function.
x = [1 2 3];
x(1) = max(x(1) - 2,0);
x
x =
0 2 3

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