Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From: Ethan Furman <ethan@stoneleaf.us>
Newsgroups: comp.lang.python
Subject: Re: What is precision of a number representation?
Date: Mon, 11 Jul 2016 15:29:42 -0700
Lines: 19
Message-ID: <mailman.199.1468276173.2295.python-list@python.org>
References: <834b1cce-38dd-474c-8915-4ff1cd6b27ec@googlegroups.com> <CALwzidmwcc0nTLtLBJm=JNAjOQNRe2umtmNXNAk=s+xoyxhU6Q@mail.gmail.com> <mailman.161.1468135349.2295.python-list@python.org> <7fcc8c21-106f-41d4-a5ba-409f3b54a56d@googlegroups.com> <CALwzidkiRh2+ttXewaQzyJhAKMjTb7AXYk=E2SxGyH_jw9o1gw@mail.gmail.com> <mailman.180.1468249505.2295.python-list@python.org> <5783c91e$0$1622$c3e8da3$5496439d@news.astraweb.com> <5783D63F.5040307@stoneleaf.us> <8560sbvqqd.fsf_-_@benfinney.id.au> <CAPTjJmqL=1cxkCK+PAdTK7Cky95B_QoUNTZkgBxKDcJ9XGf+Bw@mail.gmail.com> <57841AE9.3090508@stoneleaf.us> <57841DD6.7030405@stoneleaf.us>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Trace: news.uni-berlin.de UfvEhWY5zqr2h1Gfc7DwjwARTPMqEsC08TeW40g4gmug==
Return-Path: <ethan@stoneleaf.us>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.016
X-Spam-Evidence: '*H*': 0.97; '*S*': 0.00; 'subject:number': 0.07; 'from:addr:ethan': 0.09; 'from:addr:stoneleaf.us': 0.09; 'from:name:ethan furman': 0.09; 'message-id:@stoneleaf.us': 0.09; 'precision,': 0.16; 'received:io': 0.16; 'received:psf.io': 0.16; 'zeroes': 0.16; 'wrote:': 0.16; 'of.': 0.18; 'tells': 0.18; '(or': 0.23; 'header:In-Reply-To:1': 0.24; 'header:User-Agent:1': 0.26; 'example': 0.26; 'question': 0.27; 'actual': 0.28; '~ethan~': 0.29; 'anywhere': 0.30; 'another': 0.32; 'maybe': 0.33; 'so,': 0.35; 'could': 0.35; 'besides': 0.35; 'should': 0.36; 'there': 0.36; 'to:addr:python-list': 0.36; 'subject:?': 0.36; 'pm,': 0.36; 'subject:: ': 0.37; 'anything': 0.38; 'or,': 0.38; 'why': 0.39; 'to:addr:python.org': 0.40; 'leading': 0.61; 'more': 0.63; 'between': 0.65; 'ethan': 0.91; 'furman': 0.91
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.2.0
In-Reply-To: <57841AE9.3090508@stoneleaf.us>
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <https://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list/>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <https://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
X-Mailman-Original-Message-ID: <57841DD6.7030405@stoneleaf.us>
X-Mailman-Original-References: <834b1cce-38dd-474c-8915-4ff1cd6b27ec@googlegroups.com> <CALwzidmwcc0nTLtLBJm=JNAjOQNRe2umtmNXNAk=s+xoyxhU6Q@mail.gmail.com> <mailman.161.1468135349.2295.python-list@python.org> <7fcc8c21-106f-41d4-a5ba-409f3b54a56d@googlegroups.com> <CALwzidkiRh2+ttXewaQzyJhAKMjTb7AXYk=E2SxGyH_jw9o1gw@mail.gmail.com> <mailman.180.1468249505.2295.python-list@python.org> <5783c91e$0$1622$c3e8da3$5496439d@news.astraweb.com> <5783D63F.5040307@stoneleaf.us> <8560sbvqqd.fsf_-_@benfinney.id.au> <CAPTjJmqL=1cxkCK+PAdTK7Cky95B_QoUNTZkgBxKDcJ9XGf+Bw@mail.gmail.com> <57841AE9.3090508@stoneleaf.us>
Xref: csiph.com comp.lang.python:111300

On 07/11/2016 03:17 PM, Ethan Furman wrote:

> So, so far there is no explanation of why leading zeroes make a number
> more precise.

An example of what I mean:

174 with a precision of 3 tells us that the tenths place could be any of 
0-9, or, put another way, the actual number could be anywhere between 
174.0 to 174.9 (or maybe 173.5 to 174.5).  If we have 174 with four 
digits of precision, then the representation should be 174.0 and it's 
the hundreths we are unsure of.

So my question is: if we write 174 when could the thousands /ever/ be 
anything besides 0?

--
~Ethan~