Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail From: oyster Newsgroups: comp.lang.python Subject: what is the difference between one-line-operation and 2-line-operation Date: Mon, 25 Apr 2016 22:13:56 +0800 Lines: 62 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: news.uni-berlin.de i61Hot3bwqmA6UGwCkcVLQ1biEOB1FeE594r1SYyMLWg== Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.057 X-Spam-Evidence: '*H*': 0.89; '*S*': 0.00; '[1,': 0.09; '[2,': 0.16; 'examples?': 0.16; 'py3': 0.16; 'received:io': 0.16; 'received:psf.io': 0.16; 'subject:between': 0.16; 'to:name:python- list@python.org': 0.20; 'produces': 0.22; 'message- id:@mail.gmail.com': 0.27; 'function': 0.28; 'subject:what': 0.29; 'code': 0.30; 'says': 0.32; 'received:google.com': 0.35; 'so,': 0.35; 'text': 0.35; 'received:74.125.82': 0.35; 'but': 0.36; 'there': 0.36; 'to:addr:python-list': 0.36; 'thanks': 0.37; 'difference': 0.38; 'skip:v 20': 0.38; 'subject:the': 0.39; 'subject:-': 0.39; 'to:addr:python.org': 0.40; 'where': 0.40; 'more': 0.63; 'between': 0.65; 'received:74.125.82.41': 0.84 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to; bh=pUGwkSSi9Kf6ocfUDLr1fYgC8AArU04bg8H3d6LF6DI=; b=LaBCPkhDVFbSC+lL+1xCk3Hn3KD7AFoO0vC9W3ifuyNwaGQoOvVd/0kQn/EhGrEGPK R8EGqDaJ553wZHPTZ8/Smje5q16eGy6XhzgUiQjydoq3Zlm/4D2QaH8yb03juwWEssLG XuBjLXIPbN8bv/3TE1B90Sm9Mt57QnXApAwsOqD+RYJct7jCMl2bEMTM5/da+uVjewKn EXgur9s99r9WDX+M6JiI4xn0arlr9xYSihck9mLmai+o/5pYNe+haZuIz6mw3u5kM3a2 H2hRFGHVdzLem4Z6lBvWMcqhfpSntf5hX3cgdFWX3EiLbAaBZiFL2tnLboMToPrSJZbz 1KYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=pUGwkSSi9Kf6ocfUDLr1fYgC8AArU04bg8H3d6LF6DI=; b=dPbFkSDt6yXpMUwjy4rETh6IbfuVbVYGOv+zTgDYk0yhlJmCLtMIXBCz2pvz3dYWgx K5S6sFrVafLPbToT2JYt+Fzd8UB2Qxj9Cacotinqi7s2pX7UVRh/TT2O127HJDham/Ti whemRMCkpXRvpPBz1I80OppQdLgVM7BFdtOq60SgQvkCCbEiwwGczeyiRRBsykxbtHNr KPkagqrSGu9c7KUynfCOv9lKRSTve2CXXAhdTTx2WOkh4nEXMeBCQuWHJ1aYwCKDKQfr gGhR8nVeFUMKXccLwpzX9tduzX1PGCdTlEFlMMJaK6P3JoJ0wmcmApuiQzi7NrvvXzYX sNRg== X-Gm-Message-State: AOPr4FW23vHwqhvOSat6jWaY3vMS7k36zIeAtyfVSWo7kBOekomKJbYe7mXlw487csn5/a/D0Btum854zQe7bQ== X-Received: by 10.28.54.157 with SMTP id y29mr12041912wmh.25.1461593636739; Mon, 25 Apr 2016 07:13:56 -0700 (PDT) X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Mailman-Original-Message-ID: Xref: csiph.com comp.lang.python:107604 for a simple code [code] vexList = [1, 2, 3] print('vexList', list(vexList)) vexList=map(lambda e: e+1, vexList) print('vexList', list(vexList)) vexList = list(vexList) print('vexList', list(vexList)) vexList=map(lambda e: e*2,vexList) print('vexList', list(vexList)) [/code] py27 says [quote] ('vexList', [1, 2, 3]) ('vexList', [2, 3, 4]) ('vexList', [2, 3, 4]) ('vexList', [4, 6, 8]) [/quote] but py34 says [quote] vexList [1, 2, 3] vexList [2, 3, 4] vexList [] vexList [] [/quote] if I change the above code in to one line [code] vexList = [1, 2, 3] print('vexList', list(vexList)) vexList=list(map(lambda e: e+1, vexList)) print('vexList', list(vexList)) vexList=map(lambda e: e*2,vexList) print('vexList', list(vexList)) [/code] then py27 and py34 get same verList [quote] ('vexList', [1, 2, 3]) ('vexList', [2, 3, 4]) ('vexList', [4, 6, 8]) [/quote] I found 'filter' function behaves likely I found type(map(lambda e: e, vexList)) is in py2 type(map(lambda e: e, vexList)) is in py3 so, what produces this difference between py2 and py3 in nature? is there more examples? where can I find the text abiut his difference? Thanks