Lower case a table in lua

Question

Monster_List = {'Hunter','creature','demon'}

Monster_List = Monster_List:lower()

and what about

Attacks = {}

Attacks[1] = {'CreaTurE','MonstEr'}
Attacks[2] = {'FrOG', 'TurtLE'}

I'm sorry if this seems way too stupid, but how do I lowercase all contents of a table?

Edit: as for the second question, i did it like this, not sure if correct

for i=1,#Attacks do
    for k,v in pairs(Attacks[i]) do
    Attacks[i][k] = v:lower()
    end
end

Answer 1

Iterate the table and update the values.

lst = {'BIRD', 'Frog', 'cat', 'mOUSe'}
for k,v in pairs(lst) do
    lst[k] = v:lower()
end

table.foreach(lst, print)

Which yields:

1   bird
2   frog
3   cat
4   mouse

to handle nested tables, a recursive function would make it a breeze. something like this?

lst = {
    {"Frog", "CAT"},
    {"asdf", "mOUSe"}
}

function recursiveAction(tbl, action)
    for k,v in pairs(tbl) do
        if ('table' == type(v)) then
            recursiveAction(v, action)
        else
            tbl[k] = action(v)
        end
    end
end

recursiveAction(lst, function(i) return i:lower() end)
-- just a dirty way of printing the values for this specific lst
table.foreach(lst, function(i,v) table.foreach(v, print) end)

which yields:

1   frog
2   cat
1   asdf
2   mouse