Pad the exponential index with zeros

Question

Let's say I have a double precision value

a = 1.5838619160273860E-021

Is there a way to create a string b

b = '1.5838619160273860E-021'

Note the index has three digits here E-021 instead of E-21. I know format(int, '0.16f') can control the decimal place, but no idea how to manipulate the index.

Any input will be appreciated

@KyleFalconer that's the point, if you try to convert `a` back into a string `b` it drops the leading zero. — Mark Ransom, Aug 02 '16 at 22:45
Possible duplicate of [Python - number of digits in exponent](http://stackoverflow.com/questions/9910972/python-number-of-digits-in-exponent) — Ohad Eytan, Aug 02 '16 at 22:46

Rusty Rob · Answer 1 · 2016-08-03T01:14:23.723

0

You need another case for when its +21 instead of -21

>>> x = '1.5838619160273860E-21'
>>> a,b = x.split('E-')
>>> 'E-'.join((a,b.zfill(3)))
'1.5838619160273860E-021'

edited Aug 03 '16 at 01:14

answered Aug 02 '16 at 23:51

Rusty Rob

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Pad the exponential index with zeros

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