I have the following data that is dynamic, but below is a sample of what it might be:
# An incoming List of lists with only ints
# For exampe the incoming_list could be:
incoming_list = [[1,2]. [3]]
# The indexes are like so:
0: [1,2]
1: [3]
I then have a check_list that has some example data (will be dynamic) like so:
# A List[int] for check_list
check_list= [3]
I then need to get the first int on the incoming_list if any of the incoming lists data is in it's indexes:
# If the following were input:
incoming_list = [[1,2]. [3]]
check_list= [3]
# Then a new_list would be:
new_list = [3] because incoming_list has a list with 3 in it, and the
first element of that list is 3
##############################################################
# Another example ff the following were input:
incoming_list = [[1,2]. [3]]
check_list= [2,3]
# Then a new_list would be:
new_list = [1,3] because incoming_list has a 2 in the first index and
its first value is 1 and because incoming list has a 3 in the second index
and its first and only value is 3
I was try to do this with a set list combo but I think the List of List part is messing it up:
new_list = list(set(v for k, v in incoming_lists if int(k) in check_list))
Any ideas how to make these clean and elegant?
CodePudding user response：
In the general case it might make sense to preprocess the list into an O(1) lookup structure which can be done in linear time:
lookup = {}
for lst in reversed(incoming_list):
for x in lst:
lookup[x] = lst[0]
Then you can simply use this:
result = [lookup[x] for x in check_list]
CodePudding user response：
One simple way to achieve the desired result for the given inputs in questions. In case if you're looking for 1 line statement.
[l[0] for v in check_list for l in incoming_list if v in l]
In [33]: # EXAMPLE 1
In [34]: incoming_list = [[1,2], [3]]
In [35]: check_list= [3]
In [36]: [l[0] for v in check_list for l in incoming_list if v in l]
Out[36]: [3]
In [37]: # EXAMPLE 2
In [38]: incoming_list = [[1,2], [3]]
In [39]: check_list= [2,3]
In [40]: [l[0] for v in check_list for l in incoming_list if v in l]
Out[40]: [1, 3]
In [41]:
You can update the single line statement for the cases where we have the changes of duplicates in final result.
CodePudding user response：
Although it's not very clear what you mean, I think this should be able to work.
new_list = []
check = set(check_list)
for sublist in incoming_list:
for i in sublist:
if i in check and sublist[0] not in new_list:
new_list.append(sublist[0])
continue
print(new_list)
Output
Let's try out different values of incoming_list and check_list.
incoming_list = [[1, 2], [3]]
check_list = [2]
# Result: [1]
incoming_list = [[1, 2], [3], [2, 3, 5], [7, 8], [4, 3]]
check_list = [3]
# Result: [3, 2, 4]