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AlanPerkins APEX Code: Working with Maps inside a list
I have a list defined as List<Map<ID, MyObject__c>> and I am populating multiple maps of these objects into the list as separate entries in the list.
That all appears to work OK.
I am trying to access the records inside the maps inside the list and am running into problems:
It doesn't matter which way I seem to write the inner for loop, I get one error or another on the inner loop -
for(Integer i = counter; i == 0; i--) {
for(MyObject__c person:peopleList[i]) {
//do stuff with person
}
}
or
for(Integer i = counter; i == 0; i--) {
Map<ID, MyObject__c> p = (Map<ID, PNP_Person__c>)peopleList[i];
for(MyObject__c person:p) {
//do stuff with person
}
}
How do I reference the internal map in the list here?
The error message given here is "Initial term of field expression must be a concrete SObject: LIST:MAP:Id,SOBJECT:MyObject__c "
Thanks in advance for any assistance!
That all appears to work OK.
I am trying to access the records inside the maps inside the list and am running into problems:
It doesn't matter which way I seem to write the inner for loop, I get one error or another on the inner loop -
for(Integer i = counter; i == 0; i--) {
for(MyObject__c person:peopleList[i]) {
//do stuff with person
}
}
or
for(Integer i = counter; i == 0; i--) {
Map<ID, MyObject__c> p = (Map<ID, PNP_Person__c>)peopleList[i];
for(MyObject__c person:p) {
//do stuff with person
}
}
How do I reference the internal map in the list here?
The error message given here is "Initial term of field expression must be a concrete SObject: LIST:MAP:Id,SOBJECT:MyObject__c "
Thanks in advance for any assistance!
<code_block>
}
where <variable> must be of the same primitive or
sObject type as <list_or_set>.
Did u try something like this already?
//work on each Map
<code_block>
}
Thanks for your response. Unfortunately it hasn't helped: firstly it doesn't seem to work and secondly I need to traverse the list backwards, hence the negative counter. How can I refer to the maps inside the list by index?
as the inner loop is supposed to work on a Map, you have to use the right methods to access the contained data
for(Integer i = counter; i == 0; i--) {
Map<ID, MyObject__c> p = (Map<ID, PNP_Person__c>)peopleList[i];
for(MyObject__c person:p) { <-- p is a map here
//do stuff with person
}
}
This doesn't work since p is a Map, so the MyObject__c cannot be accessed directly. Try the values() method instead, like this:
for(Integer i = counter; i == 0; i--) {
Map<ID, MyObject__c> p = (Map<ID, PNP_Person__c>)peopleList[i];
for(MyObject__c person: p.values()) {
//do stuff with person
}
}
See also the Apex language reference, page 149 on Map methods.
Cheers,
Andreas