Extracting the SI prefix

ubermagutil provides convenience methods for determining the prefix of a value, such as pico, micro, mega, etc. The prefixes are:

import ubermagutil.units as uu

uu.si_prefixes

OrderedDict([('y', 1e-24),
             ('z', 1e-21),
             ('a', 1e-18),
             ('f', 1e-15),
             ('p', 1e-12),
             ('n', 1e-09),
             ('u', 1e-06),
             ('m', 0.001),
             ('', 1),
             ('k', 1000.0),
             ('M', 1000000.0),
             ('G', 1000000000.0),
             ('T', 1000000000000.0),
             ('P', 1000000000000000.0),
             ('E', 1e+18),
             ('Z', 1e+21),
             ('Y', 1e+24)])

From a single value, prefix can be extracted using si_multiplier:

uu.si_multiplier(5e-12)

1e-12

uu.si_multiplier(-3e6)

1000000.0

Similarly, for a list of values, the largest prefix can be determined using si_max_multiplier:

uu.si_max_multiplier([2e-3, 2e-6, 6e-9])

0.001