how to replace object in List<Map> at same index location in Flutter

Question

So lets say I have a list of objects like this:

List<Map<String, dynamic>> list = [{'a': 'red', 'b': 'blue'}, {'a': 'yellow', 'b': 'orange'}, {'a': 'green', 'b': 'purple'}];

Assuming each a and b value is unique, how would I find the object where a === yellow and replace that object with a new object like {'a': 'brown', 'b': 'white'} at the same index location in the list of the original object?

EDIT I forgot to mention, I need to remove the object first to manipulate the data and then add it back at same location.

Jhakiz · Accepted Answer · 2021-02-06 20:08:33Z

2

Try this:

  var item = list.firstWhere((i) => i["a"] == 'yellow'); // getting the item
  var index = list.indexOf(item); // Item index
  list[index] = {'a': 'brown', 'b': 'white'}; // replace item at the index

answered Feb 6, 2021 at 20:08

Jhakiz

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4 Comments

steveny909 Over a year ago

Hi @Jhakiz, thank you for your answer. I forgot to include that I need to remove first to change data and then add back at same location. I was editing my question when you answered. Could you please update your answer for that requirement? Thanks

Jhakiz Over a year ago

Which data want you add back? The new object or the existing (where a == 'yellow')??

steveny909 Over a year ago

a new object, but I may need to use data from the original object. So I think I can use the first 2 lines of your code and then do a list.removeAt(index) followed by list.insert(index, {'a': 'brown', 'b': 'white'}). Do you think that is ok or is there a better solution?

Jhakiz Over a year ago

@steveny909 those two possibilities give the same result which you're looking for. list[index] = {'a': 'brown', 'b': 'white'}; means remove the object on the index then add the new one.

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