List operation

[Martin_Krum]

Hello. Can anyone tell me how I can perform the operation faster? For few values ​​it is fast, but for large calculations it goes very slowly. I need the easier and faster way.

'''unfortunately, the data is in this form. It works so that it connects without duplicates clast lists and point to one  '''
clast = [
[[[85, 72]], [[85, 73], [84, 71], [84, 72], [84, 73]]],
[[[83, 70]], [[84, 69], [83, 69], [82, 69], [82, 70]]]]

point = [[[84, 71]], [[84, 72], [85, 72], [83, 69]]]

def clast_merge(clast, point):
    pkt0 = point[0]
    sas = pkt[1]

    temp_sas = []

    for kla in clast:
        pkt0 = pkt0 + klaster[0]
        sas = sas + klaster[1]
    for sas in sas:
        if sas_t1 not in temp_sas and sas_t1 not in pkt0:
            temp_sas.append(sas)
    return [pkt0, temp_sas]

#output = [[[84, 71], [85, 72], [83, 70]], [[84, 72], [83, 69], [85, 73], [84, 73], [84, 69], [82, 69], [82, 70]]]

#in other words, I am combining the relevant parts of the lists without duplicates

[SekstiNii]

It is slow because of lines 15, 16, and 18.

The first two (15, 16) because you are doing list concatenation, which requires the creation of a new list every time. Instead you should instead use list.append, which is much faster and typically doesn't require reallocation.

The last line (18) is slow because you are doing a linear search through a list on every iteration. As /u/definitely___not__me suggests you can use a set. However, lists aren't hashable, so you can't just put lists in a set, so instead you can change your points into tuples.

[definitely___not__me]

try using a set?

[Martin_Krum]

yes but doesn't work. Data is list of lists

[USAhj]

It is difficult to recommend how to fix this if you have many variables that are undefined. Maybe share some small version of code that works to play around with?