How to create a bytes or bytearray of given length filled with zeros in Python?
For bytes
, one may also use the literal form b'\0' * 100
.
# Python 3.6.4 (64-bit), Windows 10
from timeit import timeit
print(timeit(r'b"\0" * 100')) # 0.04987576772443264
print(timeit('bytes(100)')) # 0.1353608166305015
Update1: With constant folding in Python 3.7, the literal from is now almost 20 times faster.
Update2: Apparently constant folding has a limit:
>>> from dis import dis
>>> dis(r'b"\0" * 4096')
1 0 LOAD_CONST 0 (b'\x00\x00\x00...')
2 RETURN_VALUE
>>> dis(r'b"\0" * 4097')
1 0 LOAD_CONST 0 (b'\x00')
2 LOAD_CONST 1 (4097)
4 BINARY_MULTIPLY
6 RETURN_VALUE
This will give you 100 zero bytes:
bytearray(100)
Or filling the array with non zero values:
bytearray([1] * 100)