Python count number of digits for a value lower 1

Question

What is the easiest way in python to count the number of digits after the decimal point for a value < 1 without using string-functions?

For example i have one of the following values: 0.0001 or 0.1001 or 0.1234.

The result in all cases should be 4.

@Jean-FrançoisFabre You'll get the same answer for `0.000111`, but I think the OP wants 6 for that. — Barmar, Jan 13 '20 at 16:06
unless when using string conversions, the question makes no sense as `0.1234` is a string representation of the number. — Jean-François Fabre, Jan 13 '20 at 16:09

score 1 · Answer 1 · answered Jan 13 '20 at 16:10

1

You can do like this:

>>> x, i = 0.345223, 0
>>> while x*(10**i)//1 - x*(10**i) != 0: i+= 1
... 
>>> i
6

answered Jan 13 '20 at 16:10

Vicrobot

3

Floating point inaccuracy is likely to produce anomalous results in many cases. – Barmar Jan 13 '20 at 16:12
@Barmar For sure. – Vicrobot Jan 13 '20 at 16:13
we can use `str` function i.e. ```len(str(x).split('.')[-1]) ``` – sleeping_coder Jan 13 '20 at 16:30
@sleeping_coder op asked for non string functions – Vicrobot Jan 13 '20 at 17:16

score 0 · Answer 2 · answered Jan 13 '20 at 16:07

0

You could do a quick math trick and multiply by 10 until the number is equal to 1 or greater:

i
0.0001

count
0

while i < 1:
i = i*10
  count += 1

count
4

answered Jan 13 '20 at 16:07

Kris

This is the number of zeroes after the decimal point, not the number of digits. – Barmar Jan 13 '20 at 16:09
Another answer can be found (here)[https://stackoverflow.com/questions/6189956/easy-way-of-finding-decimal-places] – Kris Jan 13 '20 at 16:09
1

my question was not exact enough, i corrected it now. – Egirus Ornila Jan 13 '20 at 16:09
for clarification: this *only* works for numbers between 0 and 1, and will not count values after the first non-zero in the decimal. – Kris Jan 13 '20 at 16:10

2 Answers2