Message321908
Script for benchmarks:
NAME=list-slice.json
python -m perf timeit --name "l[len(l):] = reversed(l)" -l 1 -s "l = [None] * 1000000" "l[len(l):] = reversed(l)" --append $NAME
python -m perf timeit --name "l[len(l):] = l" -l 1 -s "l = [None] * 1000000" "l[len(l):] = l" --append $NAME
python -m perf timeit --name "l[::-1] = l" -s "l = [None] * 1000000" "l[::-1] = l" --append $NAME
python -m perf timeit --name "l[:] = l" -s "l = [None] * 1000000" "l[:] = l" --append $NAME
python -m perf timeit --name "l[len(l)//2:] = l" -l 1 -s "l = [None] * 1000000" "l[len(l)//2:] = l" --append $NAME
python -m perf timeit --name "l[:len(l)//2] = l" -l 1 -s "l = [None] * 1000000" "l[:len(l)//2] = l" --append $NAME
python -m perf timeit --name "l[len(l)//4:len(l)*3//4] = l" -l 1 -s "l = [None] * 1000000" "l[len(l)//4:len(l)*3//4] = l" --append $NAME
Results table:
+------------------------------+-------------------+------------------------------------+
| Benchmark | list-slice-master | list-slice |
+==============================+===================+====================================+
| l[len(l):] = reversed(l) | 8.44 ms | 5.18 ms: 1.63x faster (-39%) |
+------------------------------+-------------------+------------------------------------+
| l[len(l):] = l | 7.88 ms | 3.37 ms: 2.34x faster (-57%) |
+------------------------------+-------------------+------------------------------------+
| l[::-1] = l | 10.4 ms | 582 us: 17.85x faster (-94%) |
+------------------------------+-------------------+------------------------------------+
| l[:] = l | 10.6 ms | 86.1 ns: 123128.46x faster (-100%) |
+------------------------------+-------------------+------------------------------------+
| l[len(l)//2:] = l | 11.1 ms | 2.08 ms: 5.33x faster (-81%) |
+------------------------------+-------------------+------------------------------------+
| l[:len(l)//2] = l | 11.5 ms | 1.76 ms: 6.53x faster (-85%) |
+------------------------------+-------------------+------------------------------------+
| l[len(l)//4:len(l)*3//4] = l | 11.3 ms | 2.27 ms: 4.98x faster (-80%) |
+------------------------------+-------------------+------------------------------------+ |
|
Date |
User |
Action |
Args |
2018-07-18 18:26:09 | sir-sigurd | set | recipients:
+ sir-sigurd |
2018-07-18 18:26:09 | sir-sigurd | set | messageid: <1531938369.41.0.56676864532.issue34152@psf.upfronthosting.co.za> |
2018-07-18 18:26:09 | sir-sigurd | link | issue34152 messages |
2018-07-18 18:26:08 | sir-sigurd | create | |
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