Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.mixmin.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed2.news.xs4all.nl!xs4all!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 0.001 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'jeff': 0.04; 'variables': 0.07; 'assuming': 0.09; 'bytes,': 0.09; 'bytes.': 0.09; 'pixel': 0.09; 'pixels': 0.09; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'assume': 0.14; '"extended': 0.16; 'adjacent': 0.16; 'necessary;': 0.16; 'numpy': 0.16; 'received:80.91.229.3': 0.16; 'received:dip0.t-ipconnect.de': 0.16; 'received:plane.gmane.org': 0.16; 'received:t-ipconnect.de': 0.16; 'subject:CSV': 0.16; 'do,': 0.16; 'wrote:': 0.18; 'seems': 0.21; '>>>': 0.22; 'appears': 0.22; 'header:User-Agent:1': 0.23; 'mon,': 0.24; 'header:X-Complaints-To:1': 0.27; 'appear': 0.29; 'thus': 0.29; "doesn't": 0.30; '>>>>': 0.31; 'sep': 0.31; 'raw': 0.33; 'subject: (': 0.35; 'something': 0.35; 'but': 0.35; '+0200,': 0.36; 'skip:> 10': 0.36; 'changing': 0.37; 'loss': 0.38; 'thank': 0.38; 'to:addr:python-list': 0.38; 'does': 0.39; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'read': 0.60; 'extended': 0.61; 'skip:n 10': 0.64; 'account': 0.65; 'square': 0.74; 'much,': 0.84; 'otten': 0.84; 'skip:] 10': 0.84; 'try.': 0.91 X-Injected-Via-Gmane: http://gmane.org/ To: python-list@python.org From: Peter Otten <__peter__@web.de> Subject: Re: Works perfectly (was Re: CSV methodology) Date: Tue, 23 Sep 2014 09:59:56 +0200 Organization: None References: Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Gmane-NNTP-Posting-Host: p57bdb2b1.dip0.t-ipconnect.de User-Agent: KNode/4.13.3 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: 72 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1411459220 news.xs4all.nl 2949 [2001:888:2000:d::a6]:59571 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:78198 jayte wrote: > On Tue, 16 Sep 2014 13:22:02 +0200, Peter Otten <__peter__@web.de> wrote: > >>jayte wrote: >> >>> On Mon, 15 Sep 2014 09:29:02 +0200, Peter Otten <__peter__@web.de> >>> wrote: > > [...] > >>>> but you can read raw data >>>>with numpy. Something like >>>> >>>>with open(filename, "rb") as f: >>>> a = numpy.fromfile(f, dtype=[ >>>> ("distance", "f16"), >>>> ("iterations", "i2"), >>>> ("zc_x", "i2"), >>>> ("zc_y", "i2"), >>>> ]).reshape(1778, 1000) >>>> >>>>might do, assuming "extended double" takes 16 bytes. >>> >>> Will try. Double extended precision is ten bytes, but I assume >>> changing the "f16" to "f10" would account for that... >> >>Unfortunately it seems that numpy doesn't support "f10" > > Thus far, this appears to work perfectly: > > with open(filename, "rb") as f: > a = numpy.fromfile(f, dtype=[ > ("distance", "f8"), > ("iterations", "u2"), > ("zc_x", "u2"), > ("zc_y", "u2"), > ]) > > file.close(f) > > d = a["distance"] > i = a["iterations"] > x = a["zc_x"] > y = a["zc_y"] > > (except, of course, for the loss of precision) > > "reshape()" does not appear to be necessary; the various variables > d, i, x, y return a len() of 1778000 Assuming adjacent pixels are in the same row after b = a.reshape(h, w).T you can access a pixel as b[x, y] # without the .T (transposition) it would be b[y, x] instead of a[y*w + x] and a square of 9 pixels with b[left:left+3, top:top+3] > Again, thank you very much, > > Jeff