Matlab List Comprehension
Can I Write the Following in a One Liner? X = [1,3,5,7,9] Res = Zeros(1, Size(X,2)); for I=1: Size(X,2); Res(I) = Foo(X(I)); End; Assume That the Foo Function...
Can I write the following in a one liner?
x = [1,3,5,7,9]
res = zeros(1,size(x,2));
for i=1:size(x,2);
res(i) = foo(x(i));
end;
Assume that the foo function does not handle arrays as expected. In my case foo returns a scalar even when giving an array as argument.
In Python, for instance, it would look like this:
x = [1,3,5,7,9]
res = [foo(y) for y in x]
2 Answers
arrayfun is what you need. For example:
res = arrayfun(@foo, x)
Since foo always returns a scalar, the above will work and res will also be a vector of the same dimensions as x. If foo returns variable length output, then you will have to set 'UniformOutput' to false or 0 in the call to arrayfun. The output will then be a cell array.
Just to add to the good answer of @yoda, instead of using UniformOutput, you can also use {} brackets:
res = arrayfun(@(t){foo(t)}, x)
Also, in some occasions, foo is already vectorized.
x = 1:10;
foo = @(t)(power(t,2));
res = foo(x);
Elena Rostova holds a Master's degree in Public Health Journalism. She covers groundbreaking medical research, holistic wellness trends, mental health awareness, and nutritional science.
