Returns the nth element of a list.

Check if lst has a length greater than n, use lst[n] if possible to return the nth element, otherwise return null.
Omit the second argument, n, to get the first element of the list.

代码实现

T nth<T>(List<T> lst, [n = 0]) {
  return lst.length > n ? lst[n] : null;
}

使用样例

nth(['a', 'b', 'c'], 1); // 'b'