2018-10-03 18:59:01 +00:00
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# http://stackoverflow.com/questions/4651683/numpy-grouping-using-itertools-groupby-performance
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# setup: import numpy as np ; N = 350000 ; values = np.array(np.random.randint(0,3298,size=N),dtype='u4') ; values.sort() # noqa
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# run: grouping(values)
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# pythran export grouping(uint32 [])
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2018-04-05 22:07:33 +00:00
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def grouping(values):
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import numpy as np
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diff = np.concatenate(([1], np.diff(values)))
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idx = np.concatenate((np.where(diff)[0], [len(values)]))
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return values[idx[:-1]], np.diff(idx)
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