> But I have to agree that Python 2 had some stuff that was more "newbie-friendly" than Python 3
Also I suspect that a huge proportion of newcomer's got very confused as to why 3/2 == 1.
> But I have to agree that Python 2 had some stuff that was more "newbie-friendly" than Python 3
Also I suspect that a huge proportion of newcomer's got very confused as to why 3/2 == 1.
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> range(10)
range(0, 10)
I love iterators, but they're not an obvious concept at first.
print thing # Works in Python 2
print(thing) # the parenthesis are optional in Python 2
print(thing) # the parenthesis are required in Python 3
If you try to do something like "print(thing1, thing2)" in Python 2, you'll find that "(thing1, thing2)" is interpreted as a tuple, so Python prints it as a tuple (instead of printing thing1 and thing2 individually).
Of the top of my head come the range/enumerate/zip returns. They are really useful and needed to teach "pythonic Python". But it's hard to explain that it doesn't return a list. "It returns an iterator, that is lazy, and you need to call 'list()' on it to use it as a list..." You get my point.
You fall to a "just do like I told you. You'll get it later." that plagues a lot of other languages when being taught to newbies.
But I never said that Python 3 is less "newbie-friendly" than Python 2...
The explanation is easy, but it isn't simple.
With respect, "It always rounds down" is a terrible explanation. It explains the apparent behavior of the / operated in Python 2, but it does not really explain why. A better explanation is that the Python is both dynamically- and strongly-typed and that / does integer division on integers and "true" division on floats. For the newbie who understands these concepts, this is a far more useful explanation and metaphor; and for the newbie who doesn't, he has to learn somewhere, and frankly the / operator is not a bad example.
Floats don't really get true division either:
https://docs.python.org/3/tutorial/floatingpoint.html
And as it happens, I once explained a related problem with round() to Zed Shaw on Twitter:
(and from playing around with Perl 6, I love how decimal literals are of type Rat instead of Num; I wish Python decided to do something similar in Python 3)
Edit in response to Zed's question, in 3.6 I always just do:
print(f'{foo:.2f}')
For purposes of teaching the language to a beginner, he wants literals being rounded or divided to "just work" in a way that is unsurprising to those beginners, and there isn't any way to achieve that unless the default type of a number with a decimal point is Decimal rather than float (which isn't at all likely to happen).
The closest we are likely to get to that ideal is by introducing a Decimal literal like 0d2.125, riffing off the Hex and Octal literals (eg. 0xDEADB33F, 0o76510).
P.S., unless I am mistaken, you're just truncating the float, not actually rounding it
And I understand that it is hard for some to jump back to a newbie perspective. Some people look for performance in a programming language. Others for a thriving ecosystem. I look for usability and elegance. So I tend to look at programming languages that way.