Path: csiph.com!usenet.pasdenom.info!news.franciliens.net!dedibox.gegeweb.org!gegeweb.eu!nntpfeed.proxad.net!proxad.net!feeder1-2.proxad.net!usenet-fr.net!nerim.net!novso.com!newsfeed.xs4all.nl!newsfeed3.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.027 X-Spam-Evidence: '*H*': 0.95; '*S*': 0.00; 'else:': 0.03; 'string': 0.09; '-1)': 0.09; 'builtin': 0.09; 'subject:Help': 0.11; 'python': 0.11; 'jan': 0.12; 'sequence,': 0.16; 'wrong).': 0.16; 'subject:python': 0.16; 'wrote:': 0.18; 'form:': 0.24; 'header:In- Reply-To:1': 0.27; 'to:2**1': 0.27; 'message-id:@mail.gmail.com': 0.30; 'url:mailman': 0.30; 'work.': 0.31; 'getting': 0.31; 'prints': 0.31; 'question:': 0.31; 'url:python': 0.33; 'subject:with': 0.35; 'something': 0.35; 'but': 0.35; 'received:google.com': 0.35; 'sequence': 0.36; 'url:listinfo': 0.36; 'doing': 0.36; 'url:org': 0.36; 'should': 0.36; 'wrong': 0.37; 'list': 0.37; 'to:addr:python-list': 0.38; 'pm,': 0.38; 'to:addr:python.org': 0.39; 'url:mail': 0.40; 'first': 0.61; 'map': 0.64; 'to:addr:gmail.com': 0.65; 'series': 0.66; '100': 0.79; '2015': 0.84; 'repsonse': 0.84 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=t2qgXLZXYc7yZyugQRgIr9TAvtnSdnAVOykWlxLlVJk=; b=a0HLH3sfw8zKDHsyEcj6TRSsraJCAyYJS//fa6hDEEwgAE6YSvOahmT1ewlR47h8DJ Dl5dUZZ+lxvjHgtg1uw1ESBtyk1JyhwVoqhLLhPkTBuGbG1CtZw/GhszTRfyZp+c2o4a BtEEsLSFEZA9lVaQoHePz1jPKIrJGUAclW23E6NviDKP5cD1MpoXeWgu1ku5h/mh7egK wusQYpUmHDb9Hzl2WQ1WcwI/SPxx8R+WBDMZXkl0GoHeW7j3eg258cWF9ZFWNR5ToMRw 0jNDjoyZlvOxMbh1crcE3b+kUjIHI6xrVqBbwNPLjlhFEfEeRNy2vHB9XWxGduh0ukmn g9pw== MIME-Version: 1.0 X-Received: by 10.140.83.100 with SMTP id i91mr66743172qgd.97.1420372052951; Sun, 04 Jan 2015 03:47:32 -0800 (PST) In-Reply-To: <60e62263-6cd1-48b9-acbc-f1a0b947b8c9@googlegroups.com> References: <60e62263-6cd1-48b9-acbc-f1a0b947b8c9@googlegroups.com> Date: Sun, 4 Jan 2015 22:47:32 +1100 Subject: Re: Help with map python 2 From: Alec Taylor To: flebber , "comp.lang.python" Content-Type: text/plain; charset=UTF-8 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 32 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1420372055 news.xs4all.nl 2925 [2001:888:2000:d::a6]:34705 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:83197 map(lambda i: -i if i&1==1 else i, xrange(2, 10)) On Sun, Jan 4, 2015 at 10:34 PM, flebber wrote: > In repsonse to this question: Write a program that prints the first 100 members of the sequence 2, -3, 4, -5, 6, -7, 8. > > This is my solution it works but ugly. > > series = range(2,100) > # answer = [(x,(y* -1)) for x, y in series[::2]] > # print(answer) > answer = [] > for item in series: > if item % 2 != 0: > answer.append(item * -1) > else: > answer.append(item) > > print(answer) > > I know I should be better off doing this with map but cannot get it to work. I understand also that map returns a generator so this solution should only working in python2(correct me please if I am wrong). > > In [6]: map? > Type: builtin_function_or_method > String Form: > Namespace: Python builtin > Docstring: > map(function, sequence[, sequence, ...]) -> list > > Just getting something wrong > list(map((lambda x: x * -1 if (x%2 != 0)), series)) > -- > https://mail.python.org/mailman/listinfo/python-list