CODEWITHSUNDEEP
pythonlistmathgrouping
pylover
pylover

Reputation: 8075

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)]

Upvotes: 9

Views: 5692

Answers (2)

Raghu Paredla
Raghu Paredla

Reputation: 51

You can use DBSCAN clustering algorithm for this import from sklearn.

import numpy as np
from sklearn.cluster import DBSCAN

d = [23, 67, 110, 25, 69, 24, 102, 109]
threshold=3 # max distance between numbers
dbscan = DBSCAN(eps=3, min_samples=1)
labels = dbscan.fit(np.asarray(d).reshape(-1, 1)).labels_
print(d)
print(labels)
# [23, 67, 110, 25, 69, 24, 102, 109]
# [0, 1, 2, 0, 1, 0, 3, 2]

Upvotes: 1

georg
georg

Reputation: 215039

Like

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.

Upvotes: 23

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