Interrogate the Collection

Check empty or size

The hasContent property can be used to check whether a collection or map is empty. Alternatively, if you just wish to know the number of elements in the Collection, use the elementCount property. hasContent internally checks against elementCount, which is updated for any insertion or removal operations.

Finding an element

If you wish to check whether an element is already in the collection, the contains() method can be used. This will use the Comparator's equals() method to check the value being passed against the elements in the collection. For unsorted collections, this needs to iterate the whole collection. For sorted collection, the code can work out where the entry would need to be inserted, then check the entries before that point to see if one is unique.

For maps, containsKey() will check whether the key is in the map. Because the keys are a Collection, it runs Me.m_keySet.contains(keyVal). To check whether a value is in the map, contains(checkValue as Variant, valueComparator as Comparator) will iterate the values, comparing each using the passed Comparator. Obviously this needs to iterate the whole map, value by value.

If you wish to know at which index an element is within the collection, the getIndex() method can be used. This will use the Comparator to check the value being passed against the elements in the collection. It will return a variant that is either the index or NULL. As a result, you will need to use IsNull() for safety.

There is no provided function to get the position in the map for a value. If you have the key, the keyset is a Collection, so you can call its getIndex() method. Otherwise, you would need to iterate the map.