In principle you could use: np.equal(a,a).sum(0)
but, for unknown reason, np.equal operates only on "normal" arrays. maybe you can transform the array to arrays of numbers, for example by hash. Nadav -----הודעה מקורית----- מאת: numpy-discussion-boun...@scipy.org בשם josef.p...@gmail.com נשלח: ב 26-אוקטובר-09 20:26 אל: Discussion of Numerical Python נושא: Re: [Numpy-discussion] Multiplicity of an entry On Mon, Oct 26, 2009 at 2:12 PM, Christopher Barker <chris.bar...@noaa.gov> wrote: > Alan G Isaac wrote: >> On 10/26/2009 4:04 AM, Nils Wagner wrote: >>> how can I obtain the multiplicity of an entry in a list >>> a = ['abc','def','abc','ghij'] >> >> That's a Python question, not a NumPy question. > > but we can make it a numpy question! > > In [15]: a = np.array(['abc','def','abc','ghij']) > > > In [16]: a > Out[16]: > array(['abc', 'def', 'abc', 'ghij'], > dtype='|S4') > > In [17]: for item in set(a): > print item, (a == item).sum() It's *very* slow, when there are a large number of items. numpy creates the full boolean array for each item. see also http://projects.scipy.org/scipy/ticket/905 Josef > > abc 2 > ghij 1 > def 1 > > I'll leave pro=filing to the OP. > > -Chris > > > > -- > Christopher Barker, Ph.D. > Oceanographer > > Emergency Response Division > NOAA/NOS/OR&R (206) 526-6959 voice > 7600 Sand Point Way NE (206) 526-6329 fax > Seattle, WA 98115 (206) 526-6317 main reception > > chris.bar...@noaa.gov > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
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