Checking the decimal numbers

I have a matrix A with one column (5000x1). I want to make an if statement, which would check ONLY the decimal numbers of each row and continue with an action, if it is true. Something like this:

for i=1:5000
  if decimals of A(i)=.59333 then ...
end

Is there a simple way of controlling only the decimals? Sorry for this way of writing the code, but I didn't know how else to describe it. Thanks in advance!

Ingvar

[Jan]

Does "decimal" mean "fractional part"?

Answer 1

[Evan]

   mod(A(i),1)

Should tell you whether or not each element is a decimal number. If it returns a nonzero answer, you have a decimal.

So your code would look something like this:

for i = 1:5000
   if mod(A(i),1)
      % Your operations here
   end
end

The "modulus after division" function can also operate on vectors so, depending on what you need to do in the case of a decimal number, you could maybe even eliminate your looping altogether.

[Walter Roberson]

Caution, though, that checking exact decimals is usually a mistake: see http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[Evan]

Ah, okay. It looks like this question addresses the potential issues resulting from floating-point numbers?

http://www.mathworks.com/matlabcentral/answers/49910-mod-bug-or-something-else