Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail From: Peter Otten <__peter__@web.de> Newsgroups: comp.lang.python Subject: Re: 4D arrays Date: Tue, 01 Dec 2015 18:47:09 +0100 Organization: None Lines: 56 Message-ID: References: <08275b89237d46ae87ff574db3748dc2@cptec.inpe.br> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Trace: news.uni-berlin.de zA96jpDmuDifN+kWgMgoygVrazy64rgYIBWpkGcIZyFA== Return-Path: 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; '16,': 0.03; '21,': 0.07; '22,': 0.09; '40,': 0.09; '51,': 0.09; '75,': 0.09; 'pointless': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'python': 0.10; 'python.': 0.11; '103,': 0.16; '23,': 0.16; '24],': 0.16; '32,': 0.16; '33,': 0.16; '36,': 0.16; '37,': 0.16; '42,': 0.16; '46,': 0.16; '52,': 0.16; '55,': 0.16; '57,': 0.16; '58,': 0.16; '60,': 0.16; '61,': 0.16; '63,': 0.16; '66,': 0.16; '67,': 0.16; 'numpy': 0.16; 'received:80.91.229.3': 0.16; 'received:dip0.t-ipconnect.de': 0.16; 'received:io': 0.16; 'received:plane.gmane.org': 0.16; 'received:psf.io': 0.16; 'received:t-ipconnect.de': 0.16; 'wrote:': 0.16; '>>>': 0.20; '31,': 0.22; 'import': 0.24; 'header:User-Agent:1': 0.26; 'header:X-Complaints-To:1': 0.26; '13,': 0.29; '50,': 0.29; 'array': 0.29; "i'm": 0.30; '15,': 0.30; 'extract': 0.33; 'level': 0.35; 'but': 0.36; 'to:addr:python-list': 0.36; 'subject:: ': 0.37; 'received:org': 0.37; '12,': 0.37; 'data': 0.39; 'to:addr:python.org': 0.40; 'received:de': 0.40; '30,': 0.63; '20,': 0.66; '26,': 0.72; '71,': 0.84; '81,': 0.84; '88,': 0.84; '92,': 0.84; '95,': 0.84; 'skip:4 20': 0.91 X-Injected-Via-Gmane: http://gmane.org/ X-Gmane-NNTP-Posting-Host: p57bd96a7.dip0.t-ipconnect.de User-Agent: KNode/4.13.3 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com comp.lang.python:99807 jorge.conrado@cptec.inpe.br wrote: > I use the IDL but now I'm change to PYTHON. I have a 4D array (time, > level,lon,lat). I would like to get a 2D array for a specific time > (time1) and level (level1). In IDL I use: 2Darray = > 4Darray(time1,level1,*,*). How can I get the 2D array in Python With numpy you can use slicing. Create a 4D array with pointless data in it: >>> import numpy >>> a = numpy.arange(2*3*4*5).reshape((2, 3, 4, 5)) >>> a array([[[[ 0, 1, 2, 3, 4], [ 5, 6, 7, 8, 9], [ 10, 11, 12, 13, 14], [ 15, 16, 17, 18, 19]], [[ 20, 21, 22, 23, 24], [ 25, 26, 27, 28, 29], [ 30, 31, 32, 33, 34], [ 35, 36, 37, 38, 39]], [[ 40, 41, 42, 43, 44], [ 45, 46, 47, 48, 49], [ 50, 51, 52, 53, 54], [ 55, 56, 57, 58, 59]]], [[[ 60, 61, 62, 63, 64], [ 65, 66, 67, 68, 69], [ 70, 71, 72, 73, 74], [ 75, 76, 77, 78, 79]], [[ 80, 81, 82, 83, 84], [ 85, 86, 87, 88, 89], [ 90, 91, 92, 93, 94], [ 95, 96, 97, 98, 99]], [[100, 101, 102, 103, 104], [105, 106, 107, 108, 109], [110, 111, 112, 113, 114], [115, 116, 117, 118, 119]]]]) Extract 2D arrays: >>> a[:,2,3] array([[ 55, 56, 57, 58, 59], [115, 116, 117, 118, 119]]) >>> a[1,:,2] array([[ 70, 71, 72, 73, 74], [ 90, 91, 92, 93, 94], [110, 111, 112, 113, 114]])