MATLAB: How could numbers be displayed only in 4 digits (also in answer of sprintf)

digitnumberssprintf

Does anyone know how could numbers be displayed only in 4 digits (also in answer of sprintf) [not more than 4)

a=3.78676789728978978978978789
sprintf('%d',a)= 3.786768e+000 % but i dont need this format
sprintf('%f',a)= 3.786768  % this is better but only 4 digits is needed

I need: 3.7867 or 3.786

Best Answer

sprintf('%4.3f',pi)

doc sprintf

Related Solutions

MATLAB: How to change the field width of an exponential notation

Given >=2 digits, ensure >=3 digits:

>> val = 3.45866636216603e2;
>> str = sprintf('%.14e',val)
str =
3.45866636216603e+02
>> str = regexprep(sprintf('%.14e',val),'(?<=\D)\d\d$','0$&')
str =
3.45866636216603e+020

Given >=1 digits, ensure >=3 digits:

>> str = regexprep(sprintf('%.14e',val),{'(?<=\D)\d$','(?<=\D)\d\d$'},'0$&')
str =
3.45866636216603e+020

A general solution that can provide any number of digits:

>> num = 3; % required number of digits
>> fun = @(s)sprintf('%0*u',num,sscanf(s,'%u'));
>> str = regexprep(sprintf('%.14e',val),'\d+$','${fun($&)}')
str =
3.45866636216603e+020

MATLAB: Assigning imported data to variable names (also imported)

If you want to write efficient code that is easy to debug, read my answer below. If you wish to use eval to assign values to variables (for some reason beginners often want to do this), then read these first:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

https://www.mathworks.com/matlabcentral/answers/57445-faq-how-can-i-create-variables-a1-a2-a10-in-a-loop

A much better solution is to convert the data into a structure:

>> VarVal = [1,2,3];
>> VarNam = {'A','B','C'};
>> V = vertcat(VarNam,num2cell(VarVal));
>> S = struct(V{:});
>> S.A
ans =  1
>> S.C
ans =  3

If you have a newer MATLAB version, a table might be suitable too:

https://www.mathworks.com/help/matlab/ref/readtable.html

See, MATLAB is simple once you stop using awful eval.

Best Answer

Related Solutions

MATLAB: How to change the field width of an exponential notation

MATLAB: Assigning imported data to variable names (also imported)

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