round2

Round input to nearest multiple of arbitrary value.

Description

Everyone knows about the ROUND function for converting floating point values to their nearest whole number or integer value, but have you ever wanted to round off values to something other than whole numbers? This simple utility function does just that.

 Example 1: round PI to 2 decimal places
    >> round2(pi,0.01)
    ans =
          3.14
 
 Example 2: round PI to 4 decimal places
    >> round2(pi,1e-4)
    ans =
          3.1416
 
 Example 3: round PI to 8-bit fraction
    >> round2(pi,2^-8)
    ans =
          3.1406
 
 Examples 4-6: round PI to other multiples
    >> round2(pi,0.05)
    ans =
          3.15
    >> round2(pi,2)
    ans =
          4
    >> round2(pi,5)
    ans =
          5

• Acknowledgements: This submission has inspired the following:; Round to a Specified Number of Significant Digits, Round to Specified Digits Place, Graph Digitzer
• MATLAB release: MATLAB 6.5 (R13)

[Seema Sangari]

 

[j lee]

 

[Kai M]

 

[Asan G]

 

[Amer Zak]

Simple yet very useful!

[Niki M]

Mate you're a lifesaver I have been looking for something like this for a while.

[A Anand]

very useful

[Husam Aldahiyat]

 

[Evgeny Pr]

 

[Leo Ka]

 

[Michael]

 

[Zhang Yanxiang]

 

[Jon]

A great simple solution

[David]

I've added keyword-activated floor, ceil, and fix functionality to this; I don't know how to submit an enhancement to a file acquired here, so I'm just pasting the source below (BSD Lic.)

function z = round2(x,y,swtch)
%ROUND2 rounds number to nearest multiple of arbitrary precision.
% Z = ROUND2(X,Y) rounds X to nearest multiple of Y.
% swtch = 'floor' does the same thing, only towards -inf
% = 'ceil' same, only towards +inf
% = 'fix' same, only towards 0
%
%Example 1: round PI to 2 decimal places
% >> round2(pi,0.01)
% ans =
% 3.14
%
%Example 2: round PI to 4 decimal places
% >> round2(pi,1e-4)
% ans =
% 3.1416
%
%Example 3: round PI to 8-bit fraction
% >> round2(pi,2^-8)
% ans =
% 3.1406
%
%Examples 4-6: round PI to other multiples
% >> round2(pi,0.05)
% ans =
% 3.15
% >> round2(pi,2)
% ans =
% 4
% >> round2(pi,5)
% ans =
% 5
%Examples 7-10: round, floor, ceil, and fix PI to nearest 1/7th
%round2(pi,1/7) % recall that PI ~= 3+1/7...
% ans =
% 3.1429
% round2(pi,1/7,'floor') % ... but is < 3+1/7
% ans =
% 3
% round2(pi,1/7,'ceil')
% ans =
% 3.1429
% round2(pi,1/7,'fix')
% ans =
% 3
%
% See also ROUND, FLOOR, CEIL, FIX.

%% defensive programming
error(nargchk(2,3,nargin))
error(nargoutchk(0,1,nargout))
if numel(y)>1
  error('Y must be scalar')
end

%%
if nargin < 3
    swtch = '';
end
switch swtch
    case 'floor'
        z = floor(x/y)*y;
    case 'ceil'
        z = ceil(x/y)*y;
    case 'fix'
        z = fix(x/y)*y;
    otherwise
        z = round(x/y)*y;
end

[Rajiv]

Very Useful!

[Afsana]

thanks , it solved my problem

[JM]

Excellent

[Cameron Sparr]