[Python-Dev] RE: list comprehensions (was parsers and compilers for 2.0)

[Greg Ewing]

Two reasons why list comprehensions fit better in Python
than the equivalent map/filter/lambda constructs:

1) Scoping. The expressions in the LC have direct access to the
   enclosing scope, which is not true of lambdas in Python.

2) Efficiency. An LC with if-clauses which weed out many potential
   list elements can be much more efficient than the equivalent
   filter operation, which must build the whole list first and
   then remove unwanted items.

Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
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greg@cosc.canterbury.ac.nz	   +--------------------------------------+