Question

I’m trying to compress an array of objects that will have empty items interspersed with complete items. I want to put all the full elements at the start in the same order they started with, and the empty elements on the end.

The object in question uses a String field, “name”, and an int field, “weight”. An empty version has “no name” and 0 respectively. So an array of the type the method needs to deal with will contain something like:

• Fred | 4
• Bob | 3
• no name | 0
• Gina | 9
• no name | 0
• Yuki | 7

After feeding through the method, the array should go Fred, Bob, Gina, Yuki, no name, no name.

My thought for step one was to just figure out which were full and which weren’t, so I came up with this:

public void consolidate() {
    boolean[] fullSlots = new boolean[spaces.length];

    // pass 1: find empties
    for (int i = 0; i < spaces.length; i++) {
        fullSlots[i] = spaces[i].getName().equals("no name");
    }
}

spaces is the array of objects, getName() retrieves the name field from the object.

I’m not sure where to go from here. Suggestions?

EDIT: Okay, here’s what Infested came up with:

public void consolidate()
{
    int numberOfEmpties = 0, spacesLength = spaces.length;
    Chicken[] spaces2 = new Chicken[spacesLength];
    for(int i = 0; i < spaces.length; i++)
    {
        spaces2[i] = new Chicken(spaces[i].getName(),
                                        spaces[i].getWeight());
    }

    // pass 1: find empties
    for (int i = 0, j = 0; i < spacesLength; i++)
    {
        if (spaces2[i].getName().equals("no name") == false)
        {
            spaces[j] = new Chicken(spaces2[i].getName(),
                                        spaces2[i].getWeight());
            j++;
        }
        else
        {
            numberOfEmpties++;
        }
    }
    for (int i = spacesLength - 1; numberOfEmpties > 0 ; numberOfEmpties--, i--)
    {
       spaces[i] = new Chicken("no name", 0);
    }
}

Tested and working.

Answer 1

ill assume its a method of the class:

public void consolidate()
{
    int lengthOfSpaces = spaces.length , i, numberOfEmpties = 0;
    Type[] spacesNumberTwo = new Type[lengthOfSpaces ];

    // pass 1: find empties
    for (i = 0; i < lengthOfSpaces ; i++)
    {
        if(spaces[i].getName().equals("no name") == false)
             spacesNumberTwo[i] = new Type(spaces[i].getName(), spaces[i].getInt());
        else
          numberOfEmpties++;
    }
    for (i = lengthOfSpaces - 1; numberOfEmpties > 0 ; numberOfEmpties--, i--)
    {
           spacesNumberTwo[i] = new Type("no name", 0);
    }
    spaces = spacesNumberTwo
}