it should remove the item in list number 3?-CodePudding

I want to know how this work it should remove the item in list number 3 which is 'four' and print 'one','two','Three' why it is print three, four

here is the code:

final numbers = <String>['one', 'two', 'three', 'four'];
numbers.removeWhere((item) => item.length == 3);
print(numbers); // [three, four]`

CodePudding user response：

removeWhere :Removes all objects from this list that satisfy test.
An object o satisfies test if test(o) is true.

removeWhere will go through the list and find the matched item, means where we do our logic and return true.

You can see item.length==3 is true for 'one' and 'two' because its string length is 3, that's why these elements are removed. You can find more on List

You can expand the method like

numbers.removeWhere((item) {
  bool isItemContains3Char = item.length == 3;
  print("${isItemContains3Char}  : $item  length : ${item.length}");
  return isItemContains3Char;
});

All you need to return true based on your logic from removeWhere to remove elements.

CodePudding user response：


 final numbers = <String>['one', 'two', 'three', 'four'];
  numbers.removeAt(2);
  print(numbers);


output 
[one, two, four]