How do numbers work in Python?

Question

So, I open terminal.

> python
> 1 / 3
0
> 1.0 / 3
0.33333333333333331

Could someone tell me what the rules are when it comes to decimals. Does it matter which number when being divided carries the decimal? Is there a best practice?

If I want more decimal points, or less for that matter, do I need to use a function?

Answer 1

The division in Python < 3.0 works like in many different programming languages and the output is an integer:

>>> 3 / 2
1

If you use float for any of the parts, the output will be a float also:

>>> 3.0 / 2
1.5
>>> 3 / 2.0
1.5

But there is a solution, if you want to do division more precisely without the need to convert some of the parts into float:

>>> from __future__ import division
>>> 3 / 2
1.5

After the above you can still make "classical divisions" by using double slashes:

>>> 3 // 2
1

Is it clear enough? Did it help?