Maps within Maps

Question

Say I have a map:

Map<Lead, Map<Date, Decimal>> 

How does Map navigation work in a scenario like this?

I would like to first search the Lead, and then search the Date, in order to ultimately find the Decimal value associated to that Lead.

Answer 1

There are two ways to get to it. If you know the exact keys of both maps you can get straight to it:

Decimal myDecimal;
if (myMap.containsKey(leadRecord))
{
    myDecimal = myMap.get(leadRecord).get(dateInstance);
}

though this won't work nicely because your key is a lead sObject. Unless you have the same instance of the sObject you won't be able to match the key. I would rather use a lead Id, First Name or whatever combination of keys in order to make this work. So instead of Map <Lead <Map <Date, Decimal>> I would create Map <Id, Map <Date, Decimal>>. Then it's guaranteed that you'll get the matching value based on the correct Id.

Id myLeadId = '00Q100000000ABC';
Date myDate = System.today();

Decimal myDecimal;
if (myMap.containsKey(myLeadId))
{
    myDecimal = myMap.get(myLeadId).get(myDate);
}

Alternatively, you could iterate through the keys and perform checks for each entry. So in your current scenario you could do the following:

Id myLeadId = '00Q100000000ABC'; // This is the Id we're looking for
Date myDate = System.today(); // This is the Date we're looking for
Decimal myDecimal; // we'll store the matching value here (if there is one)

for (Lead leadRecord : myMap.keySet())
{
    if (leadRecord.Id == myLeadId)
    {
        myDecimal = myMap.get(leadRecord.Id).get(myDate);
    }
}

if (myDecimal == null)
{
    // we did not find any matches
}