使用自定义排序对String数组进行排序
我有一个String
数组:
String[] str = {"ab" , "fog", "dog", "car", "bed"}; Arrays.sort(str); System.out.println(Arrays.toString(str));
如果我使用Arrays.sort
,输出是:
[ab, bed, car, dog, fog]
但我需要实现以下排序:
FCBWHJLOAQUXMPVINTKGZERDYS
我想我需要实现Comparator
并覆盖compare
方法:
Arrays.sort(str, new Comparator() { @Override public int compare(String o1, String o2) { // TODO Auto-generated method stub return 0; } });
我该如何解决这个问题?
final String ORDER= "FCBWHJLOAQUXMPVINTKGZERDYS"; Arrays.sort(str, new Comparator() { @Override public int compare(String o1, String o2) { return ORDER.indexOf(o1) - ORDER.indexOf(o2) ; } });
您还可以添加:
o1.toUpperCase()
如果您的arrays不区分大小写。
显然,OP不仅要比较字母而且要比较字母串,所以它有点复杂:
public int compare(String o1, String o2) { int pos1 = 0; int pos2 = 0; for (int i = 0; i < Math.min(o1.length(), o2.length()) && pos1 == pos2; i++) { pos1 = ORDER.indexOf(o1.charAt(i)); pos2 = ORDER.indexOf(o2.charAt(i)); } if (pos1 == pos2 && o1.length() != o2.length()) { return o1.length() - o2.length(); } return pos1 - pos2 ; }
我会做这样的事情:
将字母放在HashTable中(让我们称之为orderMap)。 键是字母,值是ORDER中的索引。
接着:
Arrays.sort(str, new Comparator() { @Override public int compare(String o1, String o2) { int length = o1.length > o2.length ? o1.length: o2.length for(int i = 0; i < length; ++i) { int firstLetterIndex = orderMap.get(o1.charAt(i)); int secondLetterIndex = orderMap.get(o2.charAt(i)); if(firstLetterIndex == secondLetterIndex) continue; // First string has lower index letter (for example F) and the second has higher index letter (for example B) - that means that the first string comes before if(firstLetterIndex < secondLetterIndex) return 1; else return -1; } return 0; } });
为了使它不区分大小写,只需在开头的两个字符串中使用toUpperCase()。
在这里你可以找到有用的链接:
使用比较器进行自定义排序
在你的例子中,比较你需要的类的特定属性,以检查基准字符串中的char的可能性,并基于此检查它是否更好/相等/更小。
花时间改进选定的答案。 这更有效率
public static void customSort(final String order,String[] array){ String[] alphabets={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9"}; String keyword=order; for(int g=0; g() { @Override public int compare(String o1, String o2) { int pos1 = 0; int pos2 = 0; for (int i = 0; i < Math.min(o1.length(), o2.length()) && pos1 == pos2; i++) { pos1 = finalKeyword.toUpperCase().indexOf(o1.toUpperCase().charAt(i)); pos2 = finalKeyword.toUpperCase().indexOf(o2.toUpperCase().charAt(i)); } if (pos1 == pos2 && o1.length() != o2.length()) { return o1.length() - o2.length(); } return pos1 - pos2 ; } }); //Arrays.sort(array, Collections.reverseOrder()); }