Difference between two lists of lists in Python

Question

I have two lists of lists:

a = [[1,2,3],[4,5,6],[7,8,9]]
b = [[1,2,3],[9,9,9]]

I would like to get a set difference between them - expected outcome:

c = a - b = [[4,5,6],[7,8,9]].

I tried set() and set.difference() but it seems not to be able to compare lists.

Eli Harold · Accepted Answer · 2022-01-28 15:04:02Z

5

Just use list comprehensions like so:

a = [[1,2,3],[4,5,6],[7,8,9]]
b = [[1,2,3],[9,9,9]]
c = [d for d in a if d not in b]
print(c)

Output:

[[4, 5, 6], [7, 8, 9]]

answered Jan 28, 2022 at 15:04

Eli Harold

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Comments

Sam · Accepted Answer · 2022-01-28 15:04:47Z

2

You can iterate through one and check if it's in the other.

[numbers for numbers in a if numbers not in b]

answered Jan 28, 2022 at 15:04

Sam

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