Based solely on what you’ve posted (I don’t really understand why list_2 has a mix of names and amounts):

list_1 = ["$100", "$200", "$300"]
list_2 = ["bob", "$200", "sam"]

pairs = Enum.zip(list_1, list_2)

unmatched_pairs = Enum.reject(pairs, fn {l1, l2} -> l1 == l2 end)

if length(unmatched_pairs) == length(list_1) do
  false
else
  unmatched_pairs
  |> Enum.map(fn {l1, l2} -> "#{l1}: #{l2}" end)
  |> Enum.join(", ")
end

(Edited to fix a bug - was looking at length(pairs) without filtering first)

Nope, you’re not missing anything - that was a bug!

The intent is to check the length of the zipped pairs after filtering out ones like {"$200", "$200"} - if none of the pairs got filtered out, we need to return false (a “fail case”).

i too dont think i understand the 2 lists, but here is what i have for your 3 tests/examples:

iex(5)> test1 = {["$100", "$200", "$300"], ["bob",  "$200", "sam"]}
{["$100", "$200", "$300"], ["bob", "$200", "sam"]}
iex(6)> test2 = {["$100", "$200", "$300"], ["$100",  "tom", "sam"]}
{["$100", "$200", "$300"], ["$100", "tom", "sam"]}
iex(7)> test3 = {["$100", "$200", "$300"],["bob",  "tom", "sam"]}
{["$100", "$200", "$300"], ["bob", "tom", "sam"]}
iex(8)> [test1, test2, test3] |>
...(8)> Enum.map(fn {list1, list2} ->
...(8)>   Enum.zip(list1, list2) |>
...(8)>   Enum.reduce({false, []}, fn
...(8)>     {l1,l1}, {_, pairs} -> {true, pairs}
...(8)>     l1l2, {result, pairs} -> {result, [l1l2|pairs]}
...(8)>   end)
...(8)> end)
[
  true: [{"$300", "sam"}, {"$100", "bob"}],
  true: [{"$300", "sam"}, {"$200", "tom"}],
  false: [{"$300", "sam"}, {"$200", "tom"}, {"$100", "bob"}]
]

result/accumulator of the reduce is a tuple: {PASS-FAIL, PAIRS}

@czrpb and @gregvaughn
Thank you so much for your input and sorry about my delay here! That pandemic definitely is not over, got sick finally

Again, really appreciate it!