Exact number of digits output in num2str

I am building input files for Nastran and it requires exact spacing in the strings for the numbers (in string format). I am doing a lot of runs so I don't want to change my Matlab code all the time. I need to output some values with exactly 4 characters (so 1 becomes 1.00, pi becomes 3.14, 0.5 becomes 0.50, etc), but I haven't been able to figure it out yet. Using the minimum number of characters in num2str with '%2f' and rounding beforehand using round(100*n)/100 yields for pi 3.140000, probably due to roundoff error. Any help?

Answer 1

[Bjorn Gustavsson]

Well you get part of the way with %4.2f, as in

num2str(pi,'%4.2f')

that breaks down for large numbers alike pi*1e12, but then I don't know how you're supposed to squeeze that into exactly 4 chars...

HTH

Answer 2

[Bob Roos]

Thanks, didn't know that you could put the 4. there as well.