Other Ways to Make bytes Objects

So far, we’ve been mostly making bytes objects with the b'...' literal syntax; they can also be created by calling the bytes constructor with a str and an encoding name, calling the bytes constructor with an iterable of integers representing byte values, or encoding a str object per the default (or passed-in) encoding. As we’ve seen, encoding takes a str and returns the raw binary byte values of the string according to the encoding specification; conversely, decoding takes a raw bytes sequence and encodes it to its string representation—a series of possibly wide characters. Both operations create new string objects:

>>> B = b'abc'
>>> B
b'abc'

>>> B = bytes('abc', 'ascii')
>>> B
b'abc'

>>> ord('a')
97
>>> B = bytes([97, 98, 99])
>>> B
b'abc'

>>> B = 'spam'.encode()          # Or bytes()
>>> B
b'spam'
>>>
>>> S = B.decode()               # Or str()
>>> S
'spam'

广告：个人专属 VPN，独立 IP，无限流量，多机房切换，还可以屏蔽广告和恶意软件，每月最低仅 5 美元

From a larger perspective, the last two of these operations are really tools for converting between str and bytes, a topic introduced earlier and expanded upon in the next section.