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I have a nested list of lists. I need to compare a top level list to the sub lists and save the duplicates of each list into a new list. I've tried set and list comprehensions but once I try to turn those into a loop to iterate through the lists I run into issues example data below with expected returns:

topList = [list1[1,2,3], list2[3,4,5], list3[5,6,7]]
listofVals = [1,4,7]

I would expect a return of a new list of lists containing resList[[1],[4],[7]], the intent is to replicate this with more data so the sample data here is simple to provide proof of concept. I normally work in C so pointer math and just deref'ing values to do a direct compare isn't viable for my application or if it is my python fu is not the best.

Umar.H
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Richard Smith
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    I'm not 100% sure what you're asking but I think this works? `[[num] for each_list in topList for num in each_list if num in listofVals]` can you clarify what `list1` and `list2` and `list3`are and remove it from your code as it's not a proper [mcve] – Umar.H May 04 '21 at 15:33
  • its a list of ints and i just want to compare a list to that list of lists but create a new list of lists with the duplicated values, basically a big spread sheet can go down and show duplicates row by row – Richard Smith May 04 '21 at 15:34
  • I'm not sure that means _duplicated_ necessarily – 12944qwerty May 04 '21 at 15:35
  • your solution works! thank you! my list comprehension skills are not good haha – Richard Smith May 04 '21 at 15:36

1 Answers1

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@ Umar.H provided the solution thank you!

[[num] for each_list in topList for num in each_list if num in listofVals]
Richard Smith
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