Python Filtering 2 Lists
Question:
I’m trying to find a way to use one list to filter out elements of another.
Kinda like the intersect syntax but the exact opposite
lst = [0,1,2,6]
secondlst = [0,1,2,3,4,5,6]
expected outcome
[3,4,5]
Answers:
Simple way:
r = [v for v in secondlst if v not in lst]
or
list(set(secondlst).difference(lst))
Look no further than Python’s set()‘ type.
>>> lst = [0,1,2,6]
>>> secondlst = [0,1,2,3,4,5,6]
>>> set(lst).symmetric_difference(set(secondlst))
set([3, 4, 5])
Simple:
outcome = [x for x in secondlst if x not in lst]
More complex but faster if lst is large:
lstSet = set(lst)
outcome = [x for x in secondlst if x not in lstSet]
You can use filter
filter(lambda x: x not in lst, secondlst)
I’m trying to find a way to use one list to filter out elements of another.
Kinda like the intersect syntax but the exact opposite
lst = [0,1,2,6]
secondlst = [0,1,2,3,4,5,6]
expected outcome
[3,4,5]
Simple way:
r = [v for v in secondlst if v not in lst]
or
list(set(secondlst).difference(lst))
Look no further than Python’s set()‘ type.
>>> lst = [0,1,2,6]
>>> secondlst = [0,1,2,3,4,5,6]
>>> set(lst).symmetric_difference(set(secondlst))
set([3, 4, 5])
Simple:
outcome = [x for x in secondlst if x not in lst]
More complex but faster if lst is large:
lstSet = set(lst)
outcome = [x for x in secondlst if x not in lstSet]
You can use filter
filter(lambda x: x not in lst, secondlst)