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To: python-list@python.org
From: Mark Lawrence <breamoreboy@yahoo.co.uk>
Subject: Re: Python is readable
Date: Fri, 16 Mar 2012 02:16:34 +0000
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On 16/03/2012 01:53, Steven D'Aprano wrote:
> On Thu, 15 Mar 2012 00:34:47 +0100, Kiuhnm wrote:
>
>> I've just started to read
>>     The Quick Python Book (2nd ed.)
>
> Is this the one?
>
> http://manning.com/ceder/
>
>
>> The author claims that Python code is more readable than Perl code and
>> provides this example:
>>
>> --- Perl ---
>> sub pairwise_sum {
>>       my($arg1, $arg2) = @_;
>>       my(@result) = ();
>>       @list1 = @$arg1;
>>       @list2 = @$arg2;
>
> I don't understand the reason for $arg1 and $arg2. Is there some reason
> why the code couldn't do this instead?
>
>         my(@list1, @list2) = @_;
>
>
>>       for($i=0; $i<  length(@list1); $i++) {
>>           push(@result, $list1[$i] + $list2[$i]);
>>       }
>>       return(\@result);
>> }
>>
>> --- Python ---
>> def pairwise_sum(list1, list2):
>>       result = []
>>       for i in range(len(list1)):
>>           result.append(list1[i] + list2[i])
>>       return result
>> --- ---
>>
>> It's quite clear that he knows little about Perl.
>
> On the contrary -- it is quite clear that you are missing the point of
> the comparison, which is not to compare the most idiomatic Perl with the
> most idiomatic Python, but to make a direct comparison of syntax for the
> purpose of teaching beginners.
>
> The problem with idiomatic comparisons is that they often don't give you
> a feel for the overall language syntax. Instead they end up comparing
> built-ins. For example, here is how I would write the above pairwise
> addition using idiomatic RPL, the Forth-like programming language used on
> some Hewlett-Packard scientific calculators:
>
> ADD
>
> That's it. One word. Would you conclude from this that RPL is easier to
> read and write than Python? I can tell you that it is not, and I *like*
> stack-based languages that use reverse Polish Notation.
>
>
>> Here's what I would've written:
>>
>> sub pairwise_sum {
>>       my ($list1, $list2) = @_;
>>       my @result;
>>       push @result, $list1->[$_] + $list2->[$_] for (0..@$list1-1);
>>       \@result;
>> }
>>
>> Having said that, the Python code is still more readable, so there's no
>> need to misrepresent Perl that way.
>
> Speaking as somebody who doesn't know Perl, I think that your version
> would do a great disservice to Perl. Your version is shorter, but
> conciseness is often in opposition to readability. Without the author's
> version above, and the function name, I would have literally NO IDEA what
> your version does. It is virtually pure line-noise. I know enough Perl to
> guess that @result might be an array, and so guess that push pushes a
> value onto the array, but the rest might as well be written in Martian.
> Or APL.
>
> The author's version above, which you denigrate, is *much* more
> understandable than your more idiomatic Perl, especially since I can
> compare it feature to feature with the Python code.
>
> Far from misrepresenting Perl, he has gone out of his way to show Perl in
> the best possible light. Idiomatic Perl code, written by experts, is even
> more incomprehensible and unreadable to non-Perl hackers than his example.
>
>
>> Now I'm wondering whether the author will show me "good" or "bad" Python
>> code throughout the book. Should I keep reading?
>
>> From what you have show, and the sample chapters on the link above, I am
> impressed. The author is aiming to teach basic concepts and impart
> *understanding* rather than just force-feed the reader idioms which would
> be incomprehensible to them. Vern Cedar (the author) is an actual
> professional teacher, and from the samples I have seen, he knows what he
> is doing.
>
>

Well put Sir.  And (seriously) when making your comments you show the 
killer instincts of a great bowler in an Ashes Test Match, now could 
there be anything more important in life or showing greater esteem than 
that?

-- 
Cheers.

Mark Lawrence.