Whenever I try to make a list of strings (2D array), I get this error Multidimensional String arrays are not supported. This is the code I tried: names: String[30][100]. Does anyone know how to help? (version 0.3.1)

  • Use solidity or manage the array by yourself names: String[3000].
    – Ismael
    Feb 9, 2022 at 6:23
  • 2
    I figured out how to use a hashmap. Feb 10, 2022 at 12:09

2 Answers 2


I think 2D String arrays are possible now in Vyper 0.3.7. Example:

   DynArray[String[3], 10]
  • This seems only a little better than my current solution, but I already deployed my site and contract. You can achieve the same thing with the above solution. Jan 6, 2023 at 12:08
  • @thegamebegins25 Glad you found a solution that works in your contract! I'm just learning Vyper. I didn't deploy a real contract yet.
    – devdanke
    Jan 7, 2023 at 17:55
  • 1
    Differences that may be important to others: HashMap is a storage variable only. It can't be a local variable. On the other hand, DynArrays can be local or storage variables in a function. DynArrays can be passed to and returned by functions. I am not sure of the storage cost differences between HashMap and DynArray.
    – devdanke
    Jan 7, 2023 at 17:56

I figured it out, I can use a hashmap.

names: HashMap[uint256, String[30]]

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