Fredrik Lundh wrote:
it could be worth expanding them to
"if x == 1 or x == 2 or x == 3:"
though...
C:\>timeit -s "a = 1" "if a in (1, 2, 3): pass" 10000000 loops, best of 3: 0.11 usec per loop C:\>timeit -s "a = 1" "if a == 1 or a == 2 or a == 3: pass" 10000000 loops, best of 3: 0.0691 usec per loop
C:\>timeit -s "a = 2" "if a == 1 or a == 2 or a == 3: pass" 10000000 loops, best of 3: 0.123 usec per loop C:\>timeit -s "a = 2" "if a in (1, 2, 3): pass" 10000000 loops, best of 3: 0.143 usec per loop
C:\>timeit -s "a = 3" "if a == 1 or a == 2 or a == 3: pass" 10000000 loops, best of 3: 0.187 usec per loop C:\>timeit -s "a = 3" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.197 usec per loop
C:\>timeit -s "a = 4" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.225 usec per loop C:\>timeit -s "a = 4" "if a == 1 or a == 2 or a == 3: pass" 10000000 loops, best of 3: 0.161 usec per loop
Out of curiousity I ran /F's tests on my FreeBSD 4.8 box with a recent checkout:
$ ./python Lib/timeit.py -s "a = 1" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.247 usec per loop $ ./python Lib/timeit.py -s "a = 1" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.225 usec per loop $ ./python Lib/timeit.py -s "a = 2" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.343 usec per loop $ ./python Lib/timeit.py -s "a = 2" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.353 usec per loop $ ./python Lib/timeit.py -s "a = 3" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.415 usec per loop $ ./python Lib/timeit.py -s "a = 3" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.457 usec per loop $ ./python Lib/timeit.py -s "a = 4" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.467 usec per loop $ ./python Lib/timeit.py -s "a = 4" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.488 usec per loop
I then applied this patch:
--- Objects/tupleobject.c.orig Fri Jun 11 05:28:08 2004
+++ Objects/tupleobject.c Tue Feb 22 22:10:18 2005
@@ -298,6 +298,11 @@
int i, cmp; for (i = 0, cmp = 0 ; cmp == 0 && i < a->ob_size; ++i)
+ cmp = (PyTuple_GET_ITEM(a, i) == el);
+ if (cmp)
+ return cmp;
+
+ for (i = 0, cmp = 0 ; cmp == 0 && i < a->ob_size; ++i)
cmp = PyObject_RichCompareBool(el, PyTuple_GET_ITEM(a, i),
Py_EQ);
return cmp;Re-running the tests yielded:
$ ./python Lib/timeit.py -s "a = 1" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.234 usec per loop $ ./python Lib/timeit.py -s "a = 1" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.228 usec per loop $ ./python Lib/timeit.py -s "a = 2" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.239 usec per loop $ ./python Lib/timeit.py -s "a = 2" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.36 usec per loop $ ./python Lib/timeit.py -s "a = 3" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.241 usec per loop $ ./python Lib/timeit.py -s "a = 3" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.469 usec per loop $ ./python Lib/timeit.py -s "a = 4" "if a in (1, 2, 3): pass" 1000000 loops, best of 3: 0.475 usec per loop $ ./python Lib/timeit.py -s "a = 4" "if a == 1 or a == 2 or a == 3: pass" 1000000 loops, best of 3: 0.489 usec per loop
-------------------------------------------------------------------------
Andrew I MacIntyre "These thoughts are mine alone..."
E-mail: [EMAIL PROTECTED] (pref) | Snail: PO Box 370
[EMAIL PROTECTED] (alt) | Belconnen ACT 2616
Web: http://www.andymac.org/ | Australia
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