MATLAB Answers

DSP Masters

How to seperate fractional and decimal part in a real number

Asked by DSP Masters
on 16 Nov 2011
Latest activity Commented on by Walter Roberson
on 19 Sep 2016
Accepted Answer by Naz

Hi, Please help me in seperating fractional and decimal part in a real number. For example: If the value is '1.23', I need to seperate decimal part '1' and 'fractional part '0.23'.

Thanks and regards, soumya..


Jan Simon
on 16 Nov 2011

Are you talking of numbers or strings? The quotes in '1.23' might be misleading.

Jan Its my pet peeve when a poster poses a question and it is responded to with another unnecessary question. Yes, in Matlab syntax, '0.23' indicates a string, but it is really obvious that he meant 0.23. I guess my wish to responders is simply, 'Just answer the question already' !!

Jan Simon
on 13 Feb 2016

Some years later: @Jerry: Many questions in this forum are based on the inaccurate knowledge about the classes of variables. I tend to ask for a clarification instead of speculating of what seems obvious.


No products are associated with this question.

5 Answers

Answer by Naz
on 16 Nov 2011
 Accepted answer


  1 Comment

That fails on negative numbers. For negative numbers, you need fract=number-ceil(number)

Answer by Resam Makvandi
on 26 Dec 2012

i think the better way is to use: number = 1.23; integ = fix(number); fract = abs(number - integ);

it works for both negative and positive values.


Answer by Are Mjaavatten on 9 Feb 2016
Edited by Are Mjaavatten on 9 Feb 2016



The accepted answer by Naz does not use any intermediate variables. The task is to return each of the parts. Naz's solution happens to calculate one part and use it to calculate the other as well, but that does not make either one an intermediate variable.

Point taken. I should be old enough to have learned to read the problem definition. Still, I think it is nice to have a single command for the fractional part.

Jan Simon
on 13 Feb 2016

What about rem instead of mod?

abs(rem(-0.123, 1))   % =>  0.123

Answer by Kh.Ehsanur Rahman on 13 Feb 2016

what if the number is -1.23.


Answer by Walter Roberson
on 14 Feb 2016

number = -1.23
integ = fix(number)
frac = mod(abs(number),1)


What if the number is unknown and you want to compare decimal value with something..

Comparing the fraction is risky

If you want to compare to a certain number of decimal places, N, I recommend comparing round(number*10^N)

Join the 15-year community celebration.

Play games and win prizes!

Learn more
Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

MATLAB Academy

New to MATLAB?

Learn MATLAB today!