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pythonlistmathgrouping

Grouping a list of integers with nearest values


I have a list:

d = [23, 67, 110, 25, 69, 24, 102, 109]

how can I group nearest values with a dynamic gap, and create a tuple like this, what is the fastest method? :

[(23, 24, 25), (67, 69), (102, 109, 110)]

Solution

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    d = [23,67,110,25,69,24,102,109]
    
    d.sort()
    
    diff = [y - x for x, y in zip(*[iter(d)] * 2)]
    avg = sum(diff) / len(diff)
    
    m = [[d[0]]]
    
    for x in d[1:]:
        if x - m[-1][0] < avg:
            m[-1].append(x)
        else:
            m.append([x])
    
    
    print m
    ## [[23, 24, 25], [67, 69], [102, 109, 110]]
    

    Fist we calculate an average difference between sequential elements and then group together elements whose difference is less than average.