Jeffrey Harper <jhar...@yapdc.com> added the comment:
I have also determined that negative elements interfere with the frozenset
optimization described in issue6690. http://bugs.python.org/issue6690.
Here's an example program:
# test.py
from dis import dis
def x(var): return var in {1,2,3} # Note curly braces. These are sets.
def y(var): return var in {1,-2,3}
print ("dis x:")
dis(x)
print()
print("dis y:")
dis(y)
Running this produces:
C:\tmp>c:\Python32\python.exe test.py
dis x:
3 0 LOAD_FAST 0 (var)
3 LOAD_CONST 4 (frozenset({1, 2, 3}))
6 COMPARE_OP 6 (in)
9 RETURN_VALUE
dis y:
4 0 LOAD_FAST 0 (var)
3 LOAD_CONST 1 (1)
6 LOAD_CONST 4 (-2)
9 LOAD_CONST 3 (3)
12 BUILD_SET 3
15 COMPARE_OP 6 (in)
18 RETURN_VALUE
----------
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue11244>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
