Function returns from GetSpellInfo, GetItemInfo UnitAura etc...

[AJSTITAN14]

These are functions that return quite a few variables. Do I need to create variables for each value the function can return? If not how do I specify which piece of data I want from the function? Can I do it by referring to the specific returns I want to look at?

For instance:

icon, caster = GetSpellInfo(6774);

[Torhal]

All of the return values are returned, and the naming of the variables which collect them has no influence upon which are retrieved. If you call a function which has four return values and are only interested in the second and fourth, you would do this:

local _, thing_name, _, thing_desc = MakeBelieveFunction()

From this, thing_name would be the second return value, and thing_desc would be the fourth. Using the underscore is simply a common usage for a "throwaway" variable. It could just have easily been named "throwaway".

[lilsparky]

i'd just add that ignoring return values doesn't hurt you in any way. that is, if a function has 5 returns and you only need the 1st and 3rd, you could do:

local valueA, _, valueB = functionCall()

[Shirik]

Originally Posted by lilsparky i'd just add that ignoring return values doesn't hurt you in any way. that is, if a function has 5 returns and you only need the 1st and 3rd, you could do: local valueA, _, valueB = functionCall()

Actually it does hurt you slightly. The opcodes generated in this case requires a little additional work -- that is, the work of popping 2 values off the stack to ensure 3 returns. Of course, this is a minuscule difference and is probably not even testable.

[nightcracker]

If you want just one value you can use this:

select(3, GetSpellInfo(6774))

If you want for example the fifth returned value from GetSpellInfo change 3 with 5.

[Torhal]

You never want to use select() if you will be retrieving the single value multiple times - it incurs unnecessary overhead due to the function call, plus select() itself isn't very efficient.

[ravagernl]

Select loops through the given parameter with an iterator until it has arrived at the nth parameter given to select.

[Seerah]

select() also doesn't just return that one value. It returns that one plus all after.

local var3, var4, var5 = select(3, functionwith5values())