How do I get first table value in Lua

lua lua-table
Yurik picture Yurik · Jan 8, 2015 · Viewed 20.8k times · Source

Is there an easier way to do this? I need to get the very first value in a table, whose indexes are integers but might not start at [1]. Thx!

local tbl = {[0]='a',[1]='b',[2]='c'}  -- arbitrary keys
local result = nil
for k,v in pairs(tbl) do -- might need to use ipairs() instead?
    result = v
    break
end

Answer

Colonel Thirty Two picture Colonel Thirty Two · Jan 8, 2015

If the table may start at either zero or one, but nothing else:

if tbl[0] ~= nil then
    return tbl[0]
else
    return tbl[1]
end

-- or if the table will never store false
return tbl[0] or tbl[1]

Otherwise, you have no choice but to iterate through the whole table with pairs, as the keys may no longer be stored in an array but rather in an unordered hash set:

local minKey = math.huge
for k in pairs(tbl) do
    minKey = math.min(k, minKey)
end

Related questions

How to check if a table contains an element in Lua?

Is there a method for checking if a table contains a value ? I have my own (naive) function, but I was wondering if something "official" exists for that ? Or something more efficient... function table.contains(table, element) for _, value in …

Read More
How to iterate through table in Lua?

So, I have a table something along these lines: arr = { apples = { 'a', "red", 5 }, oranges = { 'o', "orange", 12 }, pears = { 'p', "green", 7 } } It doesn't seem like it's possible to access them based on their index, and the values themselves are tables, so I …

Read More
Search for an item in a Lua list

If I have a list of items like this: local items = { "apple", "orange", "pear", "banana" } how do I check if "orange" is in this list? In Python I could do: if "orange" in items: # do something Is there an equivalent …

Read More