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 Changing elements of a list to match another list rockproper Unladen Swallow Posts: 3 Threads: 2 Joined: Jul 2019 Reputation: 0 Likes received: 0 #1 Jul-11-2019, 12:56 PM (This post was last modified: Jul-11-2019, 12:57 PM by rockproper. Edited 1 time in total. Edit Reason: code block was wonky ) I am trying to iterate through a list of list and increase the first element in each sublist until it matches an integer on another list... ```list1=[[2,13,22,40],[8,13,22,40],[24,13,22,40]] reference_list=[5, 10, 30] for i in list1: while i[0]!=i in reference_list: i[0]=i[0]+1 print(list1)```Right now my output is: [[2, 13, 22, 40], [8, 13, 22, 40], [24, 13, 22, 40]] (Nothing is getting modified) My desired output is: [[5, 13, 22, 40], [10, 13, 22, 40], [30, 13, 22, 40]] (so that the first integer is increased until it matches an integer on the reference_list) I have dabbled using the set function but I can't seem to get that to work. Any ideas are appreciated! perfringo Da Bishop Posts: 1,128 Threads: 5 Joined: Jun 2018 Reputation: 116 Likes received: 255 #2 Jul-11-2019, 01:57 PM If I correctly understand the objective then no iteration is needed. You just want to replace first element in every row in matrix with value which in reference list. As indexes of rows in matrixes and elements in reference list are the same one can just: ```>>> lst = [[2,13,22,40],[8,13,22,40],[24,13,22,40]] >>> reference = [5, 10, 30] >>> for i, v in enumerate(reference): ... lst[i][0] = v ... >>> lst [[5, 13, 22, 40], [10, 13, 22, 40], [30, 13, 22, 40]] ``` I'm not 'in'-sane. Indeed, I am so far 'out' of sane that you appear a tiny blip on the distant coast of sanity. Bucky Katt, Get Fuzzy Da Bishop: There's a dead bishop on the landing. I don't know who keeps bringing them in here. ....but society is to blame. ichabod801 Number Four Posts: 4,085 Threads: 90 Joined: Sep 2016 Reputation: 253 Likes received: 1221 #3 Jul-11-2019, 02:13 PM My understanding was he wanted the first value in the sublist to be the lowest value in reference_list that is greater than or equal to the original value. So his while condition should be `while i[0] not in reference_list:`. But I agree the problem is not clearly defined. Craig "Ichabod" O'Brien - xenomind.com I wish you happiness. Recommended Tutorials: BBCode, functions, classes, text adventures « Next Oldest | Next Newest »

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