Python 2.x
Python 2.x has two types to store a string:
- str: bytes string procced as character string which is a mistake
- unicode: character string (unicode)
Both classes has same methods and are very similar.
Python 3000
Python 3000 use two very different types:
- bytes: bytes string which can be see as a list of [0..255] integers
- str: character string (unicode), exactly the same type than Python 2.x "unicode"
old str and new bytes
Differences between Python 2.x "str" and Python 3000 "bytes":
- str is immutable, bytes is mutable
- bytes "lacks" many methods: strip, lstrip, rstrip, lower, upper, etc.
choose between bytes and str
When you migration from Python 2.x to Python 3000, you have to ask youself: do I manipulate characters or bytes (integers)? "A" is a character and 65 is an integer. Examples:
- a network socket manipulate bytes
- a text parser manipulates characters (use lower, strip, etc. methods)
open issues
hash(bytes)
bytes is mutable and so it's not hashable. Hacks/Workaorounds:
- use buffer(value)
- use str8(value)
Other solutions:
- create frozenbytes type
- avoid using hash
Hash is used when bytes is a dictionary key.