How can I get the key as well as the value in an apex for loop?

Question

I have a map object which stores <Id, String> where the Id is a contact Id, and the String is a generated email message.

I have successfully looped through the map and have been able to pull out the values (The String portion) as I iterate through the map.

What I would like to be able to do is also grab the key when I grab the value. This is very simple to do in most languages, but I can't seem to find out how to do it in apex.

This is what I have right now:

Map<Id,String> mailContainer = new Map<Id,String>{};

for(String message : mailContainer.values())
{

    // This will return my message as desired
    System.debug(message);

}

What I would like is something like this:

for(String key=>message : mailContainer.values())
{

    // This will return the contact Id
    System.debug(key);

    // This will return the message
    System.debug(message);

}

Thanks in advance!

Betake

Answer 1

Iterate over the keys instead of the values:

for (Id id : mailContainer.keySet())
{
    System.debug(id);
    System.debug(mailContainer.get(id));
}

Deserve

This is so simple. I can't believe I didn't think to try that. Thanks a bunch! – Betake

Answer 2

You can't find it because it doesn't exist. Apex allows iterating over either keys or values but not associations (key, value).

Perspicuous

You can loop through the keys though, and then use those keys to grab the value. Adam's answer shows this perfectly. You are correct to the extent that I can't iterate over (key,value), but it is still possible to get the same effect with Adam's method. – Betake

Answer 3

For what it's worth, here's another way to accomplish it (slightly more verbose)...

    Map<id, string> myMap = Map<id, string> ();

    set<id> keys = myMap.keySet();
    for (id k:keys) {
        system.debug(k +' : '+ myMap.get(k));
    }

Peacetime