Make a ListView from rest API for Category only without duplication in Flutter

Question

[
  {
    "category": "Apple",
    "name": "Macbook Air"
  }, {
    "category": "Apple",
    "name": "Macbook Pro"
  }, {
    "category": "Microsoft",
    "name": "Surface"
  }, {
    "category": "Apple",
    "name": "iPad"
  }, {
    "category": "Microsoft",
    "name": "Windows"
  }, {
    "category": "Apple",
    "name": "Siri"
  }, {
    "category": "Microsoft",
    "name": "Office"
  }
]

I need to the common category into ListView from the Rest API data exampled above.

There is Apple & Microsoft are the category which common in the six data.

It's automatically done it.

Could you give a solution for this?

question from:https://stackoverflow.com/questions/65557297/make-a-listview-from-rest-api-for-category-only-without-duplication-in-flutter

Answer 1

  List getCategory(List data) {
    List list = [];
    for (var a in data) 
      if (!list.contains(a["category"]))
       list.add(a["category"]);
    return list;
  }