[Tutor] Use of List Comprehension?

[Bob Gailer]

At 09:46 PM 7/28/2004, Hee-Seng Kye wrote:
>I was wondering under which circumstances one might use list 
>comprehension.  Does it have any effect on computation time, or is it used 
>for a matter of simplicity (though could be less easier to read)?

For me list comprehension is a shorthand (idiomatic) replacement for a list 
initialization followed by one (or more nested) for loop(s), append calls 
and if statements. A lot can be said in terse code. It is easier to write 
and read. Computation time is probably faster.

Compare:
l = []
for x in y:
   if x > 3:
     l.append(x)

with:
l = [x for x in y if x > 3]

Bob Gailer
bgailer at alum.rpi.edu
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