# Java String from Map of X-Y Coordinates

coordinate-systemscoordinatesjavamapstring

I have a Map where Coords is defined as so:

``````class Coords {
int x;
int y;
public boolean equals(Object o) {
Coords c = (Coords)o;
return c.x==x && c.y==y;
}
public Coords(int x, int y) {
super();
this.x = x;
this.y = y;
}
public int hashCode() {
return new Integer(x+"0"+y);
}
}
``````

(not very good, I know, please don't tease me.) How can I now create a String where the characters are mapped from this map, for example:

``````Map<Coords, Character> map = new HashMap<Coords, Character>();
map.put(new Coords(0,0),'H');
map.put(new Coords(1,0),'e');
map.put(new Coords(2,0),'l');
map.put(new Coords(3,0),'l');
map.put(new Coords(4,0),'o');
map.put(new Coords(6,0),'!');
map put(new Coords(6,1),'!');
somehowTransformToString(map); //Hello !
//      !
``````

Thanks,
Isaac Waller
(note – it's not homework)

#### Best Solution

1. Create a comparator which can sort Coords by y and then x:

``````int d = c1.y - c2.y;
if (d == 0) d = c1.x - c2.y;
return d;
``````
2. Create a sorted map:

``````TreeMap<Coords, Character> sortedMap = new TreeMap(comparator);
sortedMap.putAll(map); // copy values from other map
``````
3. Print the values of the map in order:

``````for (Character c: map.values()) System.out.print(c);
``````
4. If you need newlines:

``````int y = -1;
for (Map.Entry<Coords, Character> e: map.entrySet()) {
if (e.y != y) {
if (y != -1) System.out.println();
y = e.y;
}
System.out.print(c);
}
``````