Opened 11 months ago
Closed 11 months ago
#23399 closed Cleanup/optimization (fixed)
Update int_to_base36
Reported by: | liminspace | Owned by: | liminspace |
---|---|---|---|
Component: | Utilities | Version: | master |
Severity: | Normal | Keywords: | |
Cc: | Triage Stage: | Unreviewed | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
I propose change function int_to_base36:
def int_to_base36(n): assert isinstance(n, (int, long)) c = '0123456789abcdefghijklmnopqrstuvwxyz' sign = '' if n < 0: sign, n = '-', -n if 0 <= n < 36: return sign + c[n] b36 = '' while n != 0: n, i = divmod(n, 36) b36 = c[i] + b36 return sign + b36
I think that it's better and faster.
Change History (5)
comment:1 Changed 11 months ago by timgraham
- Needs documentation unset
- Needs tests unset
- Patch needs improvement unset
comment:2 Changed 11 months ago by kezabelle
It's an interesting idea. For the purposes of demonstration, here's some back-of-the-napkin unscientific benchmarks, from Python 2.7.6, with sys.maxint = 9223372036854775807:
time python baseline.py
import sys print("sys.maxint is: %s" % sys.maxint) for x in xrange(0, 1000000): continue print("Complete")
Consistently yields something about the range:
real 0m0.080s
user 0m0.066s
sys 0m0.012s
the version in django:
time python original.py
import sys from django.utils.http import int_to_base36 print("sys.maxint is: %s" % sys.maxint) for x in xrange(0, 1000000): int_to_base36(i=x) print("Complete")
yields:
real 0m3.337s
user 0m3.314s
sys 0m0.020s
The version proposed by liminspace, adjusted to raise the same TypeErrors as Django's existing one:
import sys from django.utils import six print("sys.maxint is: %s" % sys.maxint) def int_to_base36(n): if n < 0: raise ValueError("Negative base36 conversion input.") if six.PY2: if not isinstance(n, six.integer_types): raise TypeError("Non-integer base36 conversion input.") if n > sys.maxint: raise ValueError("Base36 conversion input too large.") c = '0123456789abcdefghijklmnopqrstuvwxyz' sign = '' if n < 0: sign, n = '-', -n if 0 <= n < 36: return sign + c[n] b36 = '' while n != 0: n, i = divmod(n, 36) b36 = c[i] + b36 return sign + b36 for x in xrange(0, 1000000): int_to_base36(n=x) print("Complete")
yields around:
real 0m2.859s
user 0m2.847s
sys 0m0.010s
So, over the first million smallest integers, there is some small speed-up (takes about 85% of the time), by the look of those numbers.
For the top million (changed to xrange(maxint - 1000000, 100000), the times seem a little more pronounced (the new version is about 60% of the original's time):
time python baseline.py
real 0m0.069s
user 0m0.060s
sys 0m0.008s
Django's original:
time python original.py
real 0m11.840s
user 0m11.805s
sys 0m0.029s
The new version I pasted above:
time python new.py
real 0m6.897s
user 0m6.877s
sys 0m0.017s
comment:3 Changed 11 months ago by liminspace
kezabelle, try this:
def int_to_base36(n): if n < 0: raise ValueError("Negative base36 conversion input.") if six.PY2: if not isinstance(n, six.integer_types): raise TypeError("Non-integer base36 conversion input.") if n > sys.maxint: raise ValueError("Base36 conversion input too large.") c = '0123456789abcdefghijklmnopqrstuvwxyz' if n < 36: return c[n] b36 = '' while n != 0: n, i = divmod(n, 36) b36 = c[i] + b36 return b36
comment:4 Changed 11 months ago by kezabelle
First million:
time python new2.py
real 0m2.682s
user 0m2.667s
sys 0m0.012s
last million:
time python new2a.py
real 0m6.539s
user 0m6.520s
sys 0m0.015s
Also did a quick test of assert new_int_to_base36(n=x) == original_int_to_base36(i=x) for both the first and last million, which raised no errors.
comment:5 Changed 11 months ago by Tim Graham <timograham@…>
- Resolution set to fixed
- Status changed from new to closed
This implementation isn't backwards compatible with respect to the errors it raises on invalid inputs.
Some benchmarks would be helpful as far as speed goes.