Reaching the element of an array passed to a function

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Hsin-Hua Wang 2017-3-4

0
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评论： Hsin-Hua Wang 2017-3-7

I'm trying to create a function y=f(x) composed of two different parts for x < constant C & x >= C. When one pass an array A to f(x), the return would be an array B where Bij=f(Aij) How do I create a valid "if statement" in the function f? Below is the code I'm using (say I want to create a step function) What happened is since A is an array, all statement would be false Is there a way to call the "current" element in array A?

 function y=f(A)
if A >= C
y=0
elseif A<C
y=1
end
end

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Answer 1

Sky Sartorius 2017-3-4

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The first step needs to be to find the indices of the array that correspond to the conditional statement. You can use something like find for this, but logical indexing is usually preferred.

y = ones(size(A)); % Set up y.
ind = A >= C; % First, find elements of A that are greater than C.
y(ind) = 0;
y(~ind) = 1;

The last line is not absolutely necessary in this case, since we initialized y using ones, but you could put an equation here if something more complicated was needed.