Format exponent notation: start with 0

If I print a floating point f in exponential notation, I get, say:

>> sprintf('%10.3E',f)
ans =
    ' 2.091E+05'

Can Matlab always make the leading digit a zero, always, so:

>> sprintf('%someMagicHere',f)
ans =
    ' 0.209E+06'

I want this irrespective of the exponent.

(I know you print less significant digits this way)

[dpb]

Another example where C format string editing is hamstrung compared to Fortran -- there is no equivalent to the P Scale Factor Editing facility in C (and hence, not in MATLAB since it is based on the C fprintf i/o formatting library.

You'll have to manually scale the value as desired before printing.

Much would be far simpler if TMW had kept the Fortran FORMAT convention instead...

[Arjan Lampe]

Note that the two numbers are equal. I just change the notation

[dpb]

Yes, that's what P multiplier does...changes the displayed scaled factor for the exponent.

[dpb]

Yes, that's what P multiplier does...changes the displayed scaled factor for the exponent.

Answer 1

[Star Strider]

I am not certain what you are asking.

I wrote a little utility function for my own use a while back to do something like this —

a=-0.07639297;
expstr = @(x,n) [x(:).*10.^(-n*floor(log10(abs(x(:)))/abs(n)))  n*floor(log10(abs(x(:)))/abs(n))];

Result_1 = sprintf('%+0.7fE%+04d', expstr(a,4))

Result_1 = '-763.9297000E-004'

Result_2 = sprintf('%+015.7fE%+04d', expstr(a,4))

Result_2 = '-000763.9297000E-004'

Putting a leading 0 in the format (just after the %) willl fill the numeric filed to the left of the decimal with leading zeros. See Optional Operators in the formatSpec section of the sprintf documentation.

Experiment with it to get the result you want.

[Arjan Lampe]

Ok, but then I need to know the value for the exponent ahead of printing. In principle it can work though, not as simple as I had hoped...

[Star Strider]

It depends on what you want to do. The examples posted originally had different exponents, and my utility function allows that to change.

The format descriptor syntax is the same, regardless. That is a property of sprintf, fprintf, and others (such as compose) that share that syntax.