[issue21180] Cannot efficiently create empty array.array of given size, inconsistency with bytearray

[Paul Sokolovsky]

New submission from Paul Sokolovsky:

With bytearray, you can do:

>>> bytearray(3)
bytearray(b'\x00\x00\x00')

However, with arrays:

>>> array.array('i', 3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'int' object is not iterable

Given that int passed as seconf argument is not handled specially in array, I'd like to propose to make it an initial size of a zero-filled array to create. This will make it: a) consitent with bytearray; b) efficient for the scenarios where one needs to pre-create array of given length, pass to some (native) function to fill in, then do rest of processing. For the latter case, assuming that both fill-in and further processing is efficient (e.g. done by native function), the initial array creation becomes a bottleneck.

----------
components: Library (Lib)
messages: 215757
nosy: pfalcon
priority: normal
severity: normal
status: open
title: Cannot efficiently create empty array.array of given size, inconsistency with bytearray
type: performance
versions: Python 3.4

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue21180>
_______________________________________