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To: python-list@python.org
From: Fabian von Romberg <fromberg100@hotmail.com>
Subject: Re: io.BytesIO
Date: Mon, 25 Mar 2013 21:43:24 -0500
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Xref: csiph.com comp.lang.python:41846

Hi Steve,

thanks for your reply.

Actually I played around with these methods.  Whe you truncate(12468) for example, I thought the object would allocate 12468 bytes and I wanted to get that back.  The methods your mention, works only for what ha been written (obj.write()).

I think I should use io.BufferedWriter instead.

Just one question, what has better performance: BufferedWriter or BytesIO?

Thanks and regards,
Fabian

On 03/25/2013 01:54 AM, Steven D'Aprano wrote:
> On Mon, 25 Mar 2013 00:10:04 -0500, Fabian von Romberg wrote:
> 
>> Hi Steven,
>>
>>
>> actually why I need is to know how much memory has been allocated for
>> buffering.
>>
>> getsizeof gets the size of the object structure.
> 
> I can see at least four ways to get the current size of the BytesIO 
> buffer:
> 
> py> obj = io.BytesIO(b"x"*12468)
> py> obj.getbuffer().nbytes
> 12468
> py> len(obj.getvalue())
> 12468
> py> len(obj.getbuffer())
> 12468
> py> obj.seek(0, 2)
> 12468
> 
> 
> As far as I can tell, BytesIO objects do not have a fixed size buffer. 
> They will increase in size as needed, just like real file objects on a 
> disk.
> 
> 
>