is it ok to post ...

[Skaperen]

... coding tips like this?

if you have ever coded something like this:

    if n==1:
        s = ''
    else:
        s = 's'
    ...
    print('we found',n,'thing'+s)

or the shorter way many people hate:

    s = '' if n==1 else 's'
    ...
    print('we found',n,'thing'+s)

then you might want to consider doing it like this:

    s = ('s','')[n==1]
    ...
    print('we found',n,'thing'+s)

this works because booleans False and True can be used anywhere a number can be used:

Output:
>>> complex(False)
0j
>>> complex(True)
(1+0j)
>>> True/2
0.5
>>>

note that the last one will give a different result in Python2.

[ichabod801]

this works because booleans False and True can be used anywhere a number can be used:

I don't think this statement is quite correct. It suggests that booleans are not numbers. But they are.

There are three distinct numeric types: integers, floating point numbers, and complex numbers. In addition, Booleans are a subtype of integers.

[Mekire]

We have ternary statements for a reason.
Abusing indexing to accomplish the same thing, while clever, is objectively terrible.

[micseydel]

That hack is why the ternary operator was introduced, I believe. The hack doesn't short-circuit like the ternary operator does, by the way, which can occasionally lead to surprise-slow code.

[Skaperen]

this works because booleans False and True can be used anywhere a number can be used:

I don't think this statement is quite correct. It suggests that booleans are not numbers. But they are.

There are three distinct numeric types: integers, floating point numbers, and complex numbers. In addition, Booleans are a subtype of integers.

i see them as an abstraction. they do have some distinct methods.

[micseydel]

they do have some distinct methods.

Python 3:

Output:
>>> set(dir(bool)) - set(dir(int))
set()
>>> set(dir(int)) - set(dir(bool))
set()
>>> len(dir(int)), len(dir(bool))
(70, 70)
>>> set(dir(int)) == set(dir(bool))
True

???

[ichabod801]

i see them as an abstraction.

You can see them however you want. That doesn't change what they are.

[Skaperen]

i see them as an abstraction.

You can see them however you want. That doesn't change what they are.

where is what they are defined, as opposed to the implementation? typically, booleans are implemented as numbers. but that does not make them be numbers. maybe the really correct statement is that Python treats them as numbers universally and implements bools as numbers in most cases (str() doesn't, for example).

[ichabod801]

You were talking about booleans in Python. Booleans in Python are numbers. They are a subclass of int. That makes them a number.

And for the general case, given boolean algrebra, I would be curious as to how you are distinguishing booleans from numbers.

[Skaperen]

they do have some distinct methods.

Python 3:

Output:
>>> set(dir(bool)) - set(dir(int))
set()
>>> set(dir(int)) - set(dir(bool))
set()
>>> len(dir(int)), len(dir(bool))
(70, 70)
>>> set(dir(int)) == set(dir(bool))
True

???

just because it has methods with the same names does not mean they act the same.

it does look like python type bool is implemented as int in range(2) with special strings for the __str__ method. and the point is? many languages implement booleans that way. implementations don't change what booleans are.

and it's not the same as modulo 2.

do programmers need to know how python implements its types to be able to code them in python? maybe it's the other way around: seeing how their code behaves suggests how the implementation was done.

---

somewhile back (i'm not going to look for it to see who) someone said they disliked seeing ternarys being used. i had tried avoiding them. so i should go back to using them?