Number with 0 in front of it

Question

In normal math notations leading zeros do not matter in the non decimal part.

For ex.

00003123 = 3123

031 + 2 = 33

However, in python 3, if I try to do a similar operation, I find interesting results that doesn't make sense. What is happening in Python if the numbers are represented with a/many leading zeros?

Sample example in python

>>> 00003123
1619
>>> 031+2
27

`0` prefix means octal number, and behaviour of those is consistent across Python 2.x and Python 3.x. — Łukasz Rogalski, Mar 04 '20 at 14:47
Does this answer your question? [What do numbers starting with 0 mean in python?](https://stackoverflow.com/questions/11620151/what-do-numbers-starting-with-0-mean-in-python) — Kelly Bundy, Mar 04 '20 at 14:48
You should get a syntax error in Python 3. The proper octal literal in python 3 would be `0o31` — Patrick Haugh, Mar 04 '20 at 14:49
"interesting results" should mean it raises a `SyntaxError: invalid token` — Nick T, Mar 04 '20 at 14:49

bartonstanley · Accepted Answer · 2020-03-04T14:53:00.230

2

Literals beginning with zero in python 2 are octal. For example, octal 31 is 25 in base 10.

For a more complete answer, see What do numbers starting with 0 mean in python?

edited Mar 04 '20 at 14:53

answered Mar 04 '20 at 14:47

bartonstanley

1,167
12
25

score 1 · Answer 2 · answered Mar 04 '20 at 14:49

1

3 x 512 + 1 x 64 + 2 x 8 + 3 = 1619
3 x 8 + 1 + 2 = 27

This is the octal representation, now pretty outdated. Hexadecimal is preferred.

answered Mar 04 '20 at 14:49

score 0 · Answer 3 · answered Mar 04 '20 at 14:48

0

The leading 0 caused Python to interpret the number as an Octal (base 8) so 31 in base 8 is actually 25 in base 10

answered Mar 04 '20 at 14:48

KJTHoward

806
4
16

Number with 0 in front of it

3 Answers3