i agree with everyone above, kent, alan, roel... in fact, i have do a
doubletake everytime i write code like this and have to look things up
and/or play with some sample code as you all have done, just to make
sure i got it working. (kinda reminds of going back to look at a perl
script i wrote... have to check with the camel book to figure out what
i really did.)
i like alan's idea of splitting up the loops onto different lines so
that you can more clearly see the loops. the syntax does support it
altho it seems kind of clunky as:
print\
[
j
for i in a
for j in f(i)
]
originally, i thought that this would work:
print [j for j in [f(i) for i in a]]
but then realized that because of the inner grouping, it works just
the same as the original and obvious
print [f(i) for i in a]
i think the point of the EXPR in...
[EXPR for i in XXX for j in YYY for k in ZZZ...]
...is that EXPR is an expression that can be made up of components of
any of the inner loops, i.e., i, j, k, etc., so you should really just
think about the loops inside.
perhaps you can consider that you're digging a hole and jumping into
it. while inside the hole, you dig another one, and jump into *that*,
ad nauseum. back at the top, you're only collating the things you
want to save and have thrown out from all the holes you've dug
yourself into. :-)
anyone know if list comps work the same way in haskell?
-- wesley
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
"Core Python Programming", Prentice Hall, (c)2007,2001
http://corepython.com
wesley.j.chun :: wescpy-at-gmail.com
python training and technical consulting
cyberweb.consulting : silicon valley, ca
http://cyberwebconsulting.com
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