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Finding combinations of list of items (30 or so) - LynnS - Jan-25-2023
Hello, I'm having difficulty getting result running this:
from itertools import combinations input = ['R1:99','R2:111','R3:71','R4:18','R5:5','R6:10','R7:75','R8:45','R9:26','R10:7','R11:94','R12:100','R13:72','R14:31','R15:110','R16:83','R17:41','R18:51','R19:38','R20:40','R21:78','R22:104','R23:15','R24:93','R25:104','R26:36','R27:106','R28:102','R29:74','R30:14'] output = sum([list(map(list, combinations(input, i))) for i in range(len(input) + 1)], []) print(output)looks like the number of items are too many, is there a way to get this to run?
thanks in advance
RE: Finding combinations of list of items (30 or so) - deanhystad - Jan-25-2023
All possible combinations of 30 items does take a while to compute. It is funny that you expect to print the output.
from itertools import combinations
items = list('ABCDEFGHIJKLMNOPQRSTUVWXYZ')[:4]
combos = sum([list(map(list, combinations(items, i+1))) for i in range(len(items))], [])
if len(combos) < 30:
print(combos)
else:
print(len(items), len(combos))Output:[['A'], ['B'], ['C'], ['D'], ['A', 'B'], ['A', 'C'], ['A', 'D'], ['B', 'C'], ['B', 'D'], ['C', 'D'], ['A', 'B', 'C'], ['A', 'B', 'D'], ['A', 'C', 'D'], ['B', 'C', 'D'], ['A', 'B', 'C', 'D']]10 1023 15 32767 20 1048575 30 1073741823The number of combinations = 2**num_items - 1.
The time for computing the combinations of 20 items is about 2 seconds on my laptop. If the item count is 30, the number of combinations is 1024 times greater, and I would expect it to take about 2048 seconds to compute.