Performance: sets vs dicts.

Terry Reedy tjreedy at
Thu Sep 2 22:47:16 CEST 2010

On 9/1/2010 10:57 PM, rurpy at wrote:

> So while you may "think" most people rarely read
> the docs for basic language features and objects
> (I presume you don't mean to restrict your statement
> to only sets), I and most people I know *do* read
> them.  And when read them I expect them, as any good
> reference documentation does, to completely and
> accurately describe the behavior of the item I am
> reading about.  If big-O performance is deemed an
> intrinsic behavior of an (operation of) an object,
> it should be described in the documentation for
> that object.

However, big-O performance is intentionally NOT so deemed. And I have 
and would continue to argue that it should not be, for multiple reasons.

Performance is a feature of implementations, and I think they should be 

> This is not to say that a performance HOWTO or FAQ
> in addition to the reference manual would not be good.

I have writing a draft of such for CPython on my personal todo list.

Terry Jan Reedy

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