lists, maps, iterators

main.dart

void main(){
  var list = [10, "what", 4, 99];
  var list2 = <Object>[10, "what", 4, 99];
  print(list[1]);
  //print(list.runtimeType); //error in dartPad
  print(list.length);
  for(int i = 0; i<list.length; i++){
    print("Index $i contains ${list[i]}");
  }
  print(list2.runtimeType);
  var ind = 0;
  for (Object o in list2){
    print("index $ind contains $o");
    ind++;
  }
  var listBools = [true, false, true];
  print(listBools.runtimeType);
  
  //use isEmpty or isNotEmpty properties (not length)
	
  //from dartlang docs     		
  //https://www.dartlang.org/guides/language/sound-dart
  //type argument inference
  List<int> listOfInt = [];
  var listOfDouble = [3.0, 1.5, 7.5];
  var ints = listOfDouble.map((x) => x.toInt());
	print(ints.runtimeType);
  ints.forEach(print);
  
  //List<int> ints2 = List<int>.from(listOfDouble); //presence of doubles throws error
  List<int> ints3 = [];
  //I'm surprised this works to get just the 3
  for (num n in listOfDouble){
      n.toInt();
    if (n is! int) {
    } else {
      
      ints3.add(n);
    }
  }
  print(ints3);
  
  var dict = {
    "hello" : 'salut',
    "goodbye" : "au revoir",
    "thanks" : "merci"
  };
  var keys = dict.keys;
  var vals = dict.values;
  
  dict.forEach((k,v)=>print("$k : $v"));
  var iter = keys.iterator;
  var iter2 = vals.iterator;
  //can you iterate in parallel over both iterables? yup!
  while (iter.moveNext()&& iter2.moveNext()){
 			print(iter.current);
    print(iter2.current);
  }
  for (int i = 0; i<keys.length; i++){
    
    //print(keys[i]); error: no indexing
    //print(vals[i]);
  }
}