How to compare list objects with map-CodePudding

I have list type of String with elements (Example: ['Hello', 'World', 'one', 'two']).

I need to run this list and find the numbers in it.

My solution:

class DetectNumber {
  final collection = <String>['Hello', 'nine', 'world', 'one', 'two'];

  final resNumbList = <int>[];
  void res() {
    for (int i = 0; i < collection.length; i  ) {
      if (collection[i] == 'zero') {
        resNumbList.add(0);
      } else if (collection[i] == 'one') {
        resNumbList.add(1);
      } else if (collection[i] == 'two') {
        resNumbList.add(2);
      } else if (collection[i] == 'three') {
        resNumbList.add(3);
      } else if (collection[i] == 'four') {
        resNumbList.add(4);
      } else if (collection[i] == 'five') {
        resNumbList.add(5);
      } else if (collection[i] == 'six') {
        resNumbList.add(6);
      } else if (collection[i] == 'seven') {
        resNumbList.add(7);
      } else if (collection[i] == 'eight') {
        resNumbList.add(8);
      } else if (collection[i] == 'nine') {
        resNumbList.add(9);
      }
    }
    print(resNumbList); // Output: [9, 1, 2]
  }
}

Is there a shorter way to solve this task?

I have an idea of a solution via Map.

I have an idea of a solution via Map. Put String type keys and int type values in the Map

(Example: {'one': 1, 'two' : 2, ..., 'nine' : 9}).

Then compare the List with this Map. Please help me implement this.

CodePudding user response：

const digits = {'one': 1, 'two' : 2, /*...*/ 'nine' : 9};

final resNumbList = collection.where(digits.containsKey).map((e) => digits[e]);

This filters the collection for strings contained in the map and then translates these strings using the map.