pyodide/benchmark/benchmarks/grouping.py

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