Finding field widths of floats for neat printing
Andrew Gregory
andrew.gregory at npl.co.uk
Thu Apr 3 16:45:25 CEST 2003
I want to write lists of floating point numbers to text files in neat
columns with decimal points aligned, right-hand edges straight (rather
than ragged), and without unnecessary trailing zeros, e.g.
1.1 -34.67 0.006
2.0 -1.05 0.010
etc.
In order to do this I need to loop through the lists of numbers for
each column to find the field sizes m and n need to achieve this. I
can then produce a format specifier string (fss) for each column,
e.g. fss = "%" + "%i.%if" % (m,n)
Given a number, -34.67 for example is there a SMART Python way of
determining the field sizes? Obviously I need to work at less than the
precision of the machine, and ignore the fact that -34.67 might be
represented as
-34.6699999999999
I know that there are messy arithmetic methods (can use logs) - and
have implemented one.
Andrew.
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