For review: PEP 308 - If-then-else expression

Erik Max Francis max at alcyone.com
Sat Mar 1 00:25:39 CET 2003


"Chermside, Michael" wrote:

> Just want to express disagreement. I find listcomps to be EXTREMELY
> readable, and to improve the readability of the programs that I
> write. I'm not criticizing your opinions, of course, but I didn't
> want readers to think that EVERYONE dislikes listcomp syntax.

Indeed.  A Python newbie asked me a question about interpreting some
code (I believe it was some code he ran somewhere to run the
coins-out-of-a-bag probability problem; he didn't say which variant). 
He came across a list comprehension, which was made even harder to
understand since it it involved generating a list of lists (he hadn't
even been familiar with the + operator used to concatenate lists).  When
I explained to him what it meant, I then showed him the general form of
what it can do, then showed him some more readable examples, like

	name = [x.name for x in people]

At first he remarked how strange that was, within a few minutes he was
impressed by its power, and then by the end of the discussion he said,
"Well, that's one more reason for me to prefer Python to Perl."

-- 
 Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
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