On 09/17/2012 07:47 AM, Steven D'Aprano wrote:
> On Mon, 17 Sep 2012 06:46:55 -0400, Dave Angel wrote:
>
>> On 09/16/2012 11:25 PM, alex23 wrote:
>>> def readlines(f):
>>> lines = []
>>> while "f is not empty":
>>> line = f.readline()
>>> if not line: break
>>> if len(line) > 2 and line[-2:] == '|\n':
>>> lines.append(line)
>>> yield ''.join(lines)
>>> lines = []
>>> else:
>>> lines.append(line)
>> There's a few changes I'd make:
>> I'd change the name to something else, so as not to shadow the built-in,
> Which built-in are you referring to? There is no readlines built-in.
>
> py> readlines
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> NameError: name 'readlines' is not defined
>
>
> There is a file.readlines method, but that lives in a different namespace
> to the function readlines so there should be no confusion. At least not
> for a moderately experienced programmer, beginners can be confused by the
> littlest things sometimes.
You're right of course, and that's not restricted to beginners. I've
been at this for over 40 years, and I make that kind of mistake once in
a while. Fortunately, when I make such a mistake on this forum, you
usually pop in to keep me honest. When I make it in code, I either get
a runtime error, or no harm is done.
>
>> and to make it clear in caller's code that it's not the built-in one.
>> I'd replace that compound if statement with
>> if line.endswith("|\n":
>> I'd add a comment saying that partial lines at the end of file are
>> ignored.
> Or fix the generator so that it doesn't ignore partial lines, or raises
> an exception, whichever is more appropriate.
>
>
>
--
DaveA
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