grouping values in a list and storing them as sub list

Question

I am working on a problem related to coordinate systems.

This is sample data. The keys in my dictionary represent the x-coordinate and the values in the dictionary represent the y coordinate with respect to the x-coordinate.

data = {0:[1,2,10,35,36,42], 1:[50,55,60,80,85,110]}

I want to preprocess my data in such a way that if two consecutive y-coordinates share a common difference (in this case less than or equal to 10), then a sublist must be created, and all those y-coordinates should be grouped together.

For better understanding, the output should look like this.

output_data = {0:[[1,2,10],[35,36,42]], 1:[[50,55,60],[80,85],[110]]}

Can anyone please provide a solution to my problem?

Answer 1

Something like the below. The idea is to loop over the values, look back and calculate the delta.

from collections import defaultdict
DELTA = 10
data = {0:[1,2,10,35,36,42], 1:[50,55,60,80,85,110]}
result = defaultdict(list)
for k,v in data.items():
  temp = [v[0]]
  for idx,x in enumerate(v):
      if idx > 0:
        delta_found = x - temp[-1] > DELTA
        if delta_found :
          result[k].append(temp)
          temp = [x]
        else:
          temp.append(x)
  result[k].append(temp)
print(result)

output

defaultdict(<class 'list'>, {0: [[1, 2, 10], [35, 36, 42]], 1: [[50, 55, 60], [80, 85], [110]]})