[Python-ideas] Improve readability of long numeric literals

[Dan Sommers]

On Wed, 10 Feb 2016 11:50:41 +1100, Steven D'Aprano wrote:

> Floats are more complex:
> 
> 123_456.000_001e-23

Floats are less complex.  Complexes are more complex:

22j

123_456.000_001e-23j

:-)

> looks okay to me, but what about this?
> 
> 123_456_._000_001_e_-_23

Agreed:  that is no longer more readable.

All I can think of for a use case for leading underscores would be to
line up values of different lengths:

x4 = __4
x5 = _33
x6 = __4
x7 = 220

milli = 1e__-3
micro = 1e__-6
nano  = 1e__-9
pico  = 1e_-12
femto = 1e_-15

But PEP 8 already suggests otherwise:

milli = 1e-3
micro = 1e-6
nano = 1e-9
pico = 1e-12
femto = 1e-15