[Tutor] greater precision?

John Collins john at netcore.com.au
Mon Oct 29 13:45:58 CET 2012

Hi Dave,
> Valid question.  However, there are no hidden variables used in format.
> Each time you invoke the format method (it's a method of str), it starts
> from scratch using only its current arguments.  i can't think of any
> sense in which 'default' fits here, either.
Thanks, that's somewhat of a relief. In nfaces.py which outputs like
point vertex_11_22_27 0.482610585141 0.963539328269 -0.1161816686
point vertex_11_18_28 0.894075981233 0.461195737945 0.403417680839
face face_0 vertex_0_2_29
face face_0 vertex_0_25_29
face face_0 vertex_0_15_25
face face_0 vertex_0_7_15
face face_0 vertex_0_7_12
face face_0 vertex_0_2_12
normal face_0 -0.396087591388 -0.781284022758 0.482400140683
face face_1 vertex_1_15_30
there are nested outfile.write commands with logical tests! Best now
I try your suggestions - experiment, I can't break it(!), and if after a 
sleepless night, it's all pea soup, I'll log back in with this 
marvellous group of very knowledgeable and helpful folks!
> You do really need to study the format spec, to see what other
> parameters may be more useful.  What I supplied is great if all the
> digits are to the right of the decimal.
> Note, you can also use format on integers, in order to make a fixed
> number of columns, for example.  Or to get leading zeroes.  Or whatever.
> And realize that the format does not have to be "inside" the write.  So
> you can format to a string, then post-process in some way, before
> sending to the write method.
Very interesting!
> Incidentally, One of numpy or gmpy is probably a very good idea for
> you.  But as I have no experience with either, it just didn't occur to
> me.  So I'm glad Peter mentioned one of them.  The only catch I know of
> is it's an external dependency, meaning you have to download and install
> it into the Python search path.
Yes! A while back, Ramit mentioned;
"P.S. If you want large amount of accuracy with number crunching, you
  may want to look into using fixed-precision or binary math libraries.
  Try looking at scipy/numpy or using Decimal instead of floating-point
  numbers. (This is just a suggestion and may be incorrect because I
  have not yet needed such accuracy. )"

Which I just searched for and dug up!

Right, I'm off to bash this script like a beginner, and see what
emerges! :) Thanks for so many insights in one night - terrific!
Wish I'd picked this language up *years* ago - it's so foreign to
me now, yet so beautifully useful!

Cheers, John.

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