nil in the middle of a table removes all values after it?

I have found that a table with nil and more values afterwards will lose all values after the nil value. And when getting the length of the table, it will only count the values before the nil value. Example:

mytable = {1, 2, nil, 3, 4}
print(mytable[2])   -- outputs 2
print(mytable[3])   -- outputs nil
print(mytable[4])   -- outputs nil
print(mytable[5])   -- outputs nil
print(#mytable)     -- outputs 2

Is there any way to get around this and still have the nil value in the table?

That's normal behavior

#mytable returns the length of the array part of mytable, which is the part of it that starts at mytable[1] and counts up, stopping at the first nil value.

You can iterate over all the keys of a table (not just the array part) with the pairs iterator, which means you can count the indices like so:

function countKeys(t)
    local count = 0
    for _, _ in pairs(t) do
        count = count + 1
    end
    return count
end

If you only want to count integer keys, you can do that like so:

function countIntegerKeys(t)
    local count = 0
    for key, _ in pairs(t) do
        if type(key) == "number" and key % 1 == 0 then
            count = count + 1
        end
    end
    return count
end

For example:

local t = {
    [1] = "a",
    [2] = "b",
    [4] = "test",
    ["hello"] = "world"
}

print(countKeys(t), countIntegerKeys(t))

would print 4 3