To declare your map in Flutter you probably want final
:
final Map<String, int> someMap = {
"a": 1,
"b": 2,
};
Then, your update should work:
someMap["c"] = 3;
Finally, the update
function has two parameters you need to pass, the first is the key, and the second is a function that itself is given one parameter (the existing value). Example:
someMap.update("a", (value) => value + 100);
If you print the map after all of this you would get:
{a: 101, b: 2, c: 3}
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