Loop through all items in bags in World of Warcraft

wow-bag-items.lua

local function countItem(item)
    local c
    for bag=0,NUM_BAG_SLOTS do
        for slot=1,GetContainerNumSlots(bag) do
            if item == GetContainerItemID(bag,slot) then
                c=c+(select(2,GetContainerItemInfo(bag,slot)))
            end
        end
    end
    return c
end