4353755712

after append a charracter 'a', **ob_alloc** becomes 2, **ob_bytes** and **ob_start** all points to same address

a.append(ord('a'))

a.append(ord('b'))

b = bytearray(b"abcdefghijk")

After the slice operation, **ob_start** points to the real beginning of the content, and **ob_bytes** still points to the begin address of the malloced block

b[0:5] = [1,2]

as long as the slice operation is going to shrink the bytearray, and the **new_size < alloc / 2** is False, the resize operation won't shrink the real mallcoed size

b[2:6] = [3, 4]

now, in the shrink operation, the **new_size < alloc / 2** is True, the resize operation will be triggered

b[0:3] = [7,8]

The grow pattern in slice operation is same as the append operation

request size is 6, 6 < 6 * 1.125, so new allocated size is 6 + (6 >> 3) + 3 ==> 9

b[0:3] = [1,2,3,4]

what's field **ob_exports** mean ? If you need detail, you can refer to [less-copies-in-python-with-the-buffer-protocol-and-memoryviews](https://eli.thegreenplace.net/2011/11/28/less-copies-in-python-with-the-buffer-protocol-and-memoryviews) and [PEP 3118](https://www.python.org/dev/peps/pep-3118/)

buf = bytearray(b"abcdefg")

the **bytearray** implements the **buffer protocol**, and **memoryview** is able to access the internal data block via the **buffer protocol**, **mybuf** and **buf** are all sharing the same internal block

mybuf = memoryview(buf)

mybuf[1] = 3

so does **mybuf2** object(**ob_exports** doesn't change because you need to call the c function defined by **buf** object via the **buffer protocol**, **mybuf2** barely calls the slice function of **mybuf**)

mybuf2 = mybuf[:4]

mybuf2[0] = 1

**ob_exports** becomes 2

mybuf3 = memoryview(buf)

**ob_exports** becomes 0

del mybuf

del mybuf2

del mybuf3