apex:repeat group by/filter by field, show only unique values

Question

So I have an SOQL query which returns an object with these fields:

|Product Name|Option|Category|

Category could be: A B

Options could be: 1 2 3

In my VisualForce page I would like to visualise that in this form:

Category A
Option 1

Product Name

Category B
Option 2

Product Name

Option 3

Product Name

That would be something like apex:repeat and then group by Category first, then by Option and finally display Name under that. The thing is that there could be multiple entries of Category A and B, while I would only like to display the Category name once and distribute Product Names accordingly. Situation with Option field is the same as with Category.

I would appreciate your help

Answer 1

You could create a Map, sth like this:

Map <String, List <String>> = productNameListByCategoryName = new Map <String, List <String>>();

then fill the map:

if (!productNameListByCategoryName .containsKey("YOUR_CATEGORY_NAME")) {
productNameListByCategoryName .put("YOUR_CATEGORY_NAME", new List <String> {"YOUR_PRODUCT_NAME"});

} else {
    productNameListByCategoryName .get("YOUR_CATEGORY_NAME").add("YOUR_PRODUCT_NAME");
}

then all what you have to do, is to iterate it. You can do the same with Option field.