[Python] Print in scientific format with powers of ten being only multiples of 3

I haven't found a way to only get exponents which are multiples of 3, when displaying numbers in the scientific format. Neither did I succeed writing a simple custom formatting function.

Here is a quick example:
Normal behaviour using scientific notation with pythons .format():

numbers = [1.2e-2, 1.3e-3, 1.5e5, 1.6e6]

for n in numbers:
print("{:.E}".format(n))


>>> 1.20E-02
1.30E-03
1.50E+05
1.60E+06


I, however, need the following output:

>>> 12.00E-03
1.30E-03
15.00E+06
1.60E+06


Does anyone know a convenient way for me to get the desired formatting?

Continue reading...