Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed3.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path: <cameron@cskk.homeip.net>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.000
X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'python,': 0.02; 'output': 0.05; 'odd': 0.07; 'variables': 0.07; 'mail:': 0.09; 'parameter': 0.09; 'pretend': 0.09; 'teh': 0.09; 'subject:How': 0.10; 'python': 0.11; 'def': 0.12; 'calculates': 0.16; 'doing,': 0.16; 'from:addr:cs': 0.16; 'from:addr:zip.com.au': 0.16; 'from:name:cameron simpson': 0.16; 'incorrect': 0.16; 'iteration': 0.16; 'message-id:@cskk.homeip.net': 0.16; 'received:211.29': 0.16; 'received:211.29.132': 0.16; 'received:cskk.homeip.net': 0.16; 'received:homeip.net': 0.16; 'received:optusnet.com.au': 0.16; 'received:syd.optusnet.com.au': 0.16; 'rfc-822': 0.16; 'simpson': 0.16; 'variables;': 0.16; 'subject:python': 0.16; 'wrote:': 0.18; 'hey': 0.18; 'variable': 0.18; 'bit': 0.19; '(but': 0.19; 'print': 0.22; 'header:User-Agent:1': 0.23; 'tend': 0.24; 'cheers,': 0.24; 'this:': 0.26; 'header:In-Reply-To:1': 0.27; 'function': 0.29; "doesn't": 0.30; 'list:': 0.30; 'program,': 0.31; 'easy,': 0.31; 'figure': 0.32; 'run': 0.32; 'subject:with': 0.35; 'classes': 0.35; 'definition': 0.35; 'but': 0.35; 'there': 0.35; 'received:com.au': 0.36; 'doing': 0.36; 'charset:us-ascii': 0.36; 'subject:?': 0.36; 'should': 0.36; 'wrong': 0.37; 'list': 0.37; 'received:211': 0.38; 'work?': 0.38; 'to:addr:python-list': 0.38; 'does': 0.39; 'to:addr:python.org': 0.39; 'how': 0.40; 'lower': 0.61; 'new': 0.61; 'times': 0.62; 'content-disposition:inline': 0.62; 'name': 0.63; 'more': 0.64; 'therefore': 0.72; 'upper': 0.74; 'william': 0.81; 'does?': 0.84; 'mean.': 0.91; 'why?': 0.91
Date: Tue, 17 Sep 2013 09:59:45 +1000
From: Cameron Simpson <cs@zip.com.au>
To: python-list@python.org
Subject: Re: How do I calculate a mean with python?
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <571f1251-17a5-44db-a859-17a6d8065151@googlegroups.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
References: <571f1251-17a5-44db-a859-17a6d8065151@googlegroups.com>
X-Optus-CM-Score: 0
X-Optus-CM-Analysis: v=2.1 cv=bpB1Wiqi c=1 sm=1 tr=0 a=YuQlxtEQCowy2cfE5kc7TA==:117 a=YuQlxtEQCowy2cfE5kc7TA==:17 a=ZtCCktOnAAAA:8 a=PO7r1zJSAAAA:8 a=LcaDllckn3IA:10 a=Jww8p7Z7i0IA:10 a=kj9zAlcOel0A:10 a=vrnE16BAAAAA:8 a=8AHkEIZyAAAA:8 a=qWbBzqlYqigA:10 a=pGLkceISAAAA:8 a=pNGmx8qeAAAA:8 a=w1VTR14e2Vx5La_6Gp4A:9 a=aIFMf329XZmIK2S8:21 a=Zu1q-jiGs50YH5sj:21 a=CjuIK1q_8ugA:10 a=MSl-tDqOz04A:10 a=MY0F4kz7x_AA:10
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.15
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>
Newsgroups: comp.lang.python
Message-ID: <mailman.44.1379377672.18130.python-list@python.org>
Lines: 52
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1379377672 news.xs4all.nl 15938 [2001:888:2000:d::a6]:54912
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:54259

On 16Sep2013 16:33, William Bryant <gogobebe2@gmail.com> wrote:
| Hey I am new to python so go easy, but I wanted to know how to make a program that calculates the maen.
| 
| List = [15, 6, 6, 7, 8, 9, 40]
| def mean():
|     global themean, thesum
|     for i in List:
|         thecount = List.count(i)
|         thesum = sum(List)
|     themean = thesum / thecount
| 
| Why doesn't this work?

Well:

  - always include the output you get from your program, and say
    why you think it is incorrect

  - just style: we tend to name variables in lower case in Python, and
    classes with an upper case letter; "List" is a bit odd (but
    "list" is taken; how about "values"?)

  - more than style: WHY are you using global variables; just return the mean
    from the function!

  - teh variable "List" inside the function is _local_; your function does not
    accept a parameter

  - sum(List) sums the whole list
    you run it many times
    why?

  - what do you think "count()" does?

  - you should print i, thecount and thesum on each iteration of
    the list; it will help you see what your function is doing, and
    therefore to figure out what it is doing wrong

I would write a mean like this:

    def mean(values):
      return sum(values) / len(values)

There are circumstances where that is simplistic, but it is the classic
definition of the mean.

Cheers,
-- 
Cameron Simpson <cs@zip.com.au>

Microsoft Mail: as far from RFC-822 as you can get and still pretend to care.
      - Abby Franquemont-Guillory <abbyfg@tezcat.com>