Hello,
On Wed, Apr 15, 2009 at 03:01, Dan Eloff
Hi,
Can someone please explain why read() should return an immutable bytes type instead of a mutable bytearray? It's not like read() from a file and use buffer as a key in a dict is common. Certainly read() from file or stream, modify, write is very common. I don't understand why the common case pays the price in performance and simplicity. It seemed to me that the immutable bytes was described as being useful in niche situations, but it actually seems to have been favored over bytearray in Python 3.
Was there was a good reason for this decision? Or was this just an artifact in the change to two bytes types?
No, the read() method did not change from the 2.x series. It returns a new object on each call.
The reason I ask is I have a server application that is mostly stream reading/writing on the hot path and in Python 2.5 the redundant copies add up to a significant overhead, (I estimate as much as 25% from my measurements) I was looking at Python 3 as a way to solve that problem, but unfortunately it doesn't look like it will help.
Files opened in binary mode have a readinto() method, which fills the given bytearray. Is this what you are looking for? -- Amaury Forgeot d'Arc