HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

Programming Questions

miguel.si..

HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

in Programming Questions • 1 month ago

does somebody have an ideia of how to do this:

//.-----------------------------------------------------------------------------------------------------------------------------------

HashMap<Integer, int[]> test= new HashMap<Integer, int[]>();

test.put(5,???????);

//something like: test.put(5,append(int,2));

//.-----------------------------------------------------------------------------------------------------------------------------------

plz try to understand this

this is reallly important to mee!!!!

ty for your help

Replies(7)

GoToLoop

Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

Both Array & String classes have built-in support in the Java language.
And they have some personal syntaxes which the other classes lack.

An Array element can be accessed via []. And also can have a group of elements initialized w/ {}.

final HashMap<Integer, int[]> test = new HashMap();

test.put(-5, new int[] {4, 8, -6});
println(test.get(-5));
println("\n" + test.get(-5)[1]);

exit();

However, if you just wanna have whole numbers as index/key, a List is an easier composite:

final ArrayList<int[]> test = new ArrayList();

test.add(new int[] {4, 8, -6});
println(test.get(0));
println("\n" + test.get(0)[1]);

exit();

Of course, if you wanna have non-contiguous indices and/or negative 1s, you gotta stick w/ a Map anyways!

miguel.si..

Re: Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

but imagine that i want to add more number to the array in the hash map

how could i do it??

example(its wrong):

//----------------------------------------------------------------------------

final HashMap<Integer, int[]> test = new HashMap();

test.put(-5, new int[] {4, 8, -6});

println(test.get(-5));

println("\n" + test.get(-5)[1]);

println("-------------");

int[]a = new int[0];

a = append(a,test.get(-5));

a =append(test.get(-5),5);

test.put(-5, a );

println("\n" + test.get(-5)[1]);

exit();

GoToLoop

Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

A Java Array has a fixed size. It means once created, its length can't be changed!
Functions like append() and shorten() don't actually change an Array's length.
Rather they create another 1 w/ a different length!
In short, if we want a dynamic-sized composite, we're better off using a List instead.

Some experiments I did about it:

import java.util.List;
import java.util.Arrays;

final List<List<Integer>> test = new ArrayList();

test.add(new ArrayList(Arrays.asList(4, 8, -6)));
println(test.get(0));
println(test.get(0).get(1) + "\n");

test.get(0).set(2, 10);
println(test.get(0));

test.get(0).add(30);
println(test.get(0));

test.get(0).remove(1);
println(test.get(0) + "\n");

println(test.size() + "\t" + test.get(0).size());

exit();

PhiLho

Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

In other words, you need:
final HashMap<Integer, List<Integer>> test = new HashMap<Integer, List<Integer>>();
(the second <...> can be omitted in Processing but generates a warning in regular Java, so I never omit it, except in Java 7 where I can write an empty diamond <>).

GoToLoop

Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

Lotsa Java 7 features that Processing's pre-compiler doesn't allow:

no empty diamond <>
no binary literal
no String for switch()
no _ as separator visualizer for number literal -> 150_321
no UNICODE labels
no other @ usages apart from @Override

Java in general:

no nested enum
no <> for double classes -> HashMap.Entry<String, Integer>

It needs a serious IQ update.

Also, #define and #ifdef would be gr8!

hamzeen

Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

this should work for you..

void setup(){

HashMap<Integer, int[]> test= new HashMap<Integer, int[]>();

test.put(5,new int[]{1,2});

println(test.get(5));

noLoop();

}

PhiLho

Re: Re: HashMap<Integer, int[]> test= new HashMap<Integer, int[]>(); How can i define the int array???

1 month ago

Looks like the already given and accepted solution above...

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