When using Ink to store data in a Mapping with a tuple Key, how do you iterate through all the elements in a tuple?


  • Can you provide an example?
    – Bruno
    Sep 6, 2022 at 19:35
  • yes. as in the erc721 example. operator_approvals: Mapping<(AccountId, AccountId), ()> Sep 6, 2022 at 21:24
  • so for each account there are many operators accounts. how to iterate through the operators for each main account. Sep 6, 2022 at 21:36

2 Answers 2


Looping through tuples is not ideal (to put it lightly) since they are not heterogeneous.

You could tackle this in two ways:


As per this issue, right now it can't possible to iterate over storage.

  • so would you need to store another mapping of tuples that maps to an array of Ids for each element in the tuple? Sep 26, 2022 at 2:44

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