[EMAIL PROTECTED] wrote: > Lonnie> List comprehensions appear to store their temporary result in a > Lonnie> variable named "_[1]" (or presumably "_[2]", "_[3]" etc for > Lonnie> nested comprehensions) > > Known issue. Fixed in generator comprehensions. Dunno about plans to fix > it in list comprehensions. I believe at some point in the future they may > just go away or become syntactic sugar for a gen comp wrapped in a list() > call.
The latter, starting in Python 3.0. It won't be fixed before Python 3.0 because it has the potential to break existing 2.x code. From PEP 289: """List comprehensions also "leak" their loop variable into the surrounding scope. This will also change in Python 3.0, so that the semantic definition of a list comprehension in Python 3.0 will be equivalent to list(<generator expression>). Python 2.4 and beyond should issue a deprecation warning if a list comprehension's loop variable has the same name as a variable used in the immediately surrounding scope.""" Source: http://www.python.org/dev/peps/pep-0289/ Also mentioned in PEP 3100. Doesn't look like the deprecation warning was ever implemented for 2.4, though. On my 2.4.3: >>> def f(): [x for x in range(10)] print x >>> f() 9 >>> # no warning yet.. 2.5 is in alpha now, hopefully the warning will be added. --Ben -- http://mail.python.org/mailman/listinfo/python-list
