Description
Bug report
bytearray slice assignment for bytes-like object is much slower than that for bytearray
On my machine:
python -m timeit -s "a=bytearray(4096);b=b'x'*1024;" "a[:1024]=b"
1000000 loops, best of 5: 296 nsec per loop
python -m timeit -s "a=bytearray(4096);b=memoryview(b'x'*1024);" "a[:1024]=b"
1000000 loops, best of 5: 293 nsec per loop
python -m timeit -s "a=bytearray(4096);b=bytearray(b'x'*1024);" "a[:1024]=b"
5000000 loops, best of 5: 80.4 nsec per loop
On official Python playground(https://www.python.org/shell/):
import timeit
timeit.main(["-s", "a=bytearray(4096);b=b'x'*1024;", "a[:1024]=b"])
1000000 loops, best of 5: 272 nsec per loop
timeit.main(["-s", "a=bytearray(4096);b=memoryview(b'x'*1024);", "a[:1024]=b"])
1000000 loops, best of 5: 268 nsec per loop
timeit.main(["-s", "a=bytearray(4096);b=bytearray(b'x'*1024);", "a[:1024]=b"])
5000000 loops, best of 5: 78.8 nsec per loop
Your environment
- CPython versions tested on: 3.11.1
- Operating system and architecture: Windows 10 22H2 x86-64