如何像 SQL 中的 ORDER BY 子句一样操作数组？

Question

我的数据已放入数组中，但不幸的是不是按照我想要的顺序...

String[][] databaseToArray = {
  //{"Name", "Channel", "Description", "Amount", "isReady"},
    {"John", "Nick",    "likes",       "2",      "yes"    },
    {"Drew", "MTV",     "dislikes",    "4",      "no"     },
    {"Fred", "CNN",     "okay",        "3",      "no"     },
    {"Beth", "Fox",     "valid",       "1",      "yes"    }
};

我如何操作这个数组，以便当我循环它时，顺序是按 amount ，类似于 SELECT * FROM “databaseToArray” ORDER BY “Amount” 又名

String[][] reorganizedArray = {
  //{"Name", "Channel", "Description", "Amount", "isReady"},
    {"Beth", "Fox",     "valid",       "1",      "yes"    },
    {"John", "Nick",    "likes",       "2",      "yes"    },
    {"Fred", "CNN",     "okay",        "3",      "no"     },
    {"Drew", "MTV",     "dislikes",    "4",      "no"     }
};

Answer 1

您需要将 Comparator 传递给 Arrays.sort 方法。我已经 5 年没有学过 Java了，但是应该很容易做到。也许有人可以清理我即将写的这个例子，因为我很确定我会出错。

String[][] databaseToArray = {
  //{"Name", "Channel", "Description", "Amount", "isReady"},
    {"John", "Nick",    "likes",       "2",      "yes"    },
    {"Drew", "MTV",     "dislikes",    "4",      "no"     },
    {"Fred", "CNN",     "okay",        "3",      "no"     },
    {"Beth", "Fox",     "valid",       "1",      "yes"    }
};

Arrays.sort(databaseToArray, new Comparator<String[]>() {
    public int compare(String[] a, String[] b) {
        return a[3].compareTo(b[3]);
    }
});

Answer 2

我在处理网站上找到了排序方法，但这仅适用于一维数组...

http: //processing.org/reference/sort_.html

   float[] a = { 3, 5, 2, 4, 1 };
   a = sort(a);
   println(a);
// Prints 1, 2, 3, 4, 5