Change the exponent precision
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I need to display, using fprintf, an exponent with this precision 1.7800e-005. I can set the precision for the 1.7800 part but do not know how to set the precision for the 005 part. I don't want the default 05, I need 005. Thanks
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Star Strider
on 2 Oct 2015
Edited: Star Strider
on 4 May 2021
I didn’t realise MATLAB no longer printed out three-digit exponents by default. This may seem a long way round, but ‘expstr’ works for both +ve and -ve exponents:
Q1 = pi/10000;
expstr = @(x) [x*10.^floor(1-log10(abs(x))) floor(log10(abs(x)))];
Result = sprintf('%.4fe%+04d', expstr(Q1))
Result =
3.1416e-004
EDIT — Added abs(x) to log10 arguments in the ‘expstr’ function.
—————
EDIT — (4 May 2021 at 16:38)
Correcting my ‘expstr’ function to not crash on a 0 argument turned out to be surprisingly straightforward —
expstr = @(x) [x(:).*10.^ceil(-log10(abs(x(:)+(x==0)))) floor(log10(abs(x(:)+(x==0))))]; % Updated: 2021 05 04
Given:
Q1 = [-pi*1000; 0; pi/1000];
Result = sprintf('%8.4fe%+04d\n', expstr(Q1).')
.
3 Comments
Star Strider
on 3 Oct 2015
When I first began using MATLAB 20+ years ago (always on Windows), a three-digit exponent was standard. I don’t remember when it changed (I have other things to keep track of), but in R2015b, a two-digit exponent is standard. Thus the reason for the specific three-digit exponent format here.
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