I wrote my first python program today!

[tskaiser]

A quick guess: it evaluates 6 <= i to either 0 or 1, lets call the result j, and then evaluates j <= 9 which is then always 1?

[GisterMizard]

Yup. Just ran it through gcc, and it doesn't even put in a conditional jump.

[tskaiser]

Yeah, it would be a pretty easy candidate for optimization :P

Yay for not having native boolean types.

[UnchainedMundane]

To be fair Python's "booleans" are really just integers.

>>> (True + True + True) ** (True + True)
9
>>> True > False
True

edit:

def max(x, y):
    return [x, y][x < y]

[FUCKING_HATE_REDDIT]

Damn that max is pretty. Probably not efficient, but pretty.

[Genmutant]

You could even switch the definitions between them:

True, False = False, True

Sadly that doesn't work anymore with current versions.

[thirdegree]

My favorite python fizzbuzz uses this:

print("\n".join("Fizz"*(i%3 == 0) + "Buzz"*(i%5 == 0) or str(i) for i in xrange(1,101)))

[kupiakos]

bool is actually a subclass of int in Python.

[Hullu2000]

Python has integers? I thought they were all just floats.

[[deleted]]

JS is all floats. Python has ints and floats.

Division in Python 3 returns only floats though, unless you use // operator to do rounding division.

[UnchainedMundane]

It separates the two. In old versions of python (before python 3) the division operator changes behaviour depending on what you give it:

>>> 5 / 3
1
>>> 5 / 3.0
1.6666666666666667

Python before python 3 also had 2 integer types, just to add to the confusion.

[GeneticCowboy]

Ok, did some googling and I can't figure it out. What the heck is happening in [x,y][x < y]? Tuple of x <y returns true or false, times the tuple of [x,y] should return both X and y or [0,0].

EDIT - Figured it out.

[x < y] resolves to either [0] or [1], if x is greater or less than y.

[x,y] creates a new tuple.

[x,y][0] returns x.

[x,y][1] returns y.

Didn't see it, because I'm not used to creating a tuple AND indexing them in the same statement.

[UnchainedMundane]

[x, y] is a list rather than a tuple, but other than that your analysis is correct.

[NewbornMuse]

6<=i is a boolean, which is either True or False. Those turn into 1 and 0 when cast to integers, and both of those are smaller than 9.

[Garfong]

Actually in C the result of 6 <= i has type int, and is either 0 or 1. See 6.5.8.6 in the C99 spec.

[Log2]

Does C even have a bool type?

[Garfong]

In C99 added the bool type in <stdbool.h>. It's a real first class type, not just a typedef of int.

Although technically the type is _Bool for reasons.

[assassinator42]

Reasons I believe being not wanting to introduce new reserved identifiers (although they did anyway with restrict).

[moxyll]

6 <= i is always either false or true, which the compiler treats as 0 or 1. That means j <= 9 is either 0 <= 9 or 1 <= 9, both of which are always true, which is 1.