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From: "Prasad, Ramit" <ramit.prasad@jpmorgan.com>
To: Python <python-list@python.org>
Subject: RE: len() on mutables vs. immutables
Thread-Topic: len() on mutables vs. immutables
Thread-Index: AQHNrVVpw35MazyeyU+GZFCxCjgf6pe/pWYA///KIsCAAEksgP//yf7Q
Date: Thu, 18 Oct 2012 20:26:18 +0000
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Xref: csiph.com comp.lang.python:31683

Ian Kelly wrote:=0D=0A> Sent: Thursday, October 18, 2012 2:39 PM=0D=0A> To:=
 Python=0D=0A> Subject: Re: len() on mutables vs=2E immutables=0D=0A> =0D=
=0A> On Thu, Oct 18, 2012 at 1:18 PM, Prasad, Ramit=0D=0A> <ramit=2Eprasad@=
jpmorgan=2Ecom> wrote:=0D=0A> > Why does pointer arithmetic work for dicts?=
 I would think the position=0D=0A> > of a value would be based on the hash =
of the key and thus "random" for=0D=0A> > the context of this conversation=
=2E=0D=0A> =0D=0A> It doesn't=2E  len() on CPython dicts is O(1) because th=
e dict keeps=0D=0A> track of how many items it contains=2E  It needs to do =
this anyway so=0D=0A> that it can determine when to grow the internal hash =
table=2E=0D=0A=0D=0AThat is what I was thinking "should" happen=2E Thanks f=
or the =0D=0Aclarification Ian=2E=0D=0A=0D=0A=0D=0ARamit Prasad=0D=0A=0D=0A=
=0D=0AThis email is confidential and subject to important disclaimers and=
=0D=0Aconditions including on offers for the purchase or sale of=0D=0Asecur=
ities, accuracy and completeness of information, viruses,=0D=0Aconfidential=
ity, legal privilege, and legal entity disclaimers,=0D=0Aavailable at http:=
//www=2Ejpmorgan=2Ecom/pages/disclosures/email=2E