Is there a more efficient way to Select
data into a String
collection e.g. Set<String>
than using a for loop
Set<String> allTopicSet = new Set<String>();
for (Topic t: [select name from Topic]) {
allTopicSet.add(t.Name);
}
There isn't, you can only get the Id of a list of objects easily by converting the list to a map and getting the keyset. (See I just want the IDs?)
I'm afraid you're stuck to looping over the list, and adding them manually like you are doing now.