Question

我有一个格式数组

array
(
     0 => array ( id = 1, name = chimpanzee, address = Singapore )
     1 => array ( id = 2, name = meeting, address = USA  )
     2 => array ( id = 3, name = dynasty, address = Singapore  )
     3 => array ( id = 4, name = chocolate, address = Netherland  )
     4 => array ( id = 5, name = bananas, address = Singapore  )
     5 => array ( id = 6, name = fantasy, address = USA  )
     6 => array ( id = 7, name = football, address = England)
)

我想根据每个子阵列中的地址字段将其分组为一个新数组。

array
(
    Singapore => array
    (
         0 => array ( id = 1, name = chimpanzee, address = Singapore )
         2 => array ( id = 3, name = dynasty, address = Singapore  )
         4 => array ( id = 5, name = bananas, address = Singapore  )
    )

    USA => array
    (
         1 => array ( id = 2, name = meeting, address = USA  )
         5 => array ( id = 6, name = fantasy, address = USA  )
    )

    Netherland => array
    (
         3 => array ( id = 4, name = chocolate, address = Netherland  )
    )

    England => array
    (
         6 => array ( id = 7, name = football, address = England)
    )
)

Answer 1

正如@ Rizier123所说，使用循环检查所有数组条目并将它们复制到一个新的（已排序）数组，如下所示：

import java.util.ArrayList;

public class Menu {

    private ArrayList<String> meals;

    public Menu() {
        this.meals = new ArrayList<String>();
    }

     public void addMeal(String meal) {
         if (!meals.contains(meal)) {
         meals.add(meal);      
     }
    }
      public void printMeals() {
          if (!meals.isEmpty())
          System.out.println(this.meals);
      }

      public void clearMenu(){
          meals.removeAll(meals);
      }

}

如何按名称将数组分组到子数组

1 个答案: