Removing First Value in Checkbox Table - checkbox

Question

I am making a program in Lua that has a large amount of checkboxes. Each checkbox is ID-ed from 1 to 100 in the order they appear. When a checkbox is checked, a table saves the checkbox ID and sorts it, and when it is unchecked, the table is searched for that checkbox ID and then removes it if it finds it and then sorts the table again.
However, I am having problems with the first value not removing itself. It will get removed if I check an earlier ID value and then uncheck it, but not if I try unchecking it first.
Here is the code:
switchCounter = 0
switchID = {}
--if checkbox-is-checked then
switchID[switchCounter] = checkbox.id
switchCounter = switchCounter + 1
table.sort(switchID)
--elseif checkbox-is-unchecked then
for p = 0, #switchID do
if switchID[p] == checkbox.id then
table.remove(switchID, p)
end
end
switchCounter = #switchID+1
table.sort(switchID)
The table is not altered or touched after this point (yet). It works perfectly as long as it is not the first value I am trying to remove, upon which nothing happens.
This code is utilizing the Corona SDK if that is relevant to answering.

Answer 1

You're confusing Lua by starting your table index at 0. In Lua, tables are 1-indexed, unlike what you're used to from most programming languages. Unfortunately, most of this code actually still works even though you're using the wrong index range. However, when you call table.remove on the first element, since your first element has index 0, you'll end up calling table.remove(switchID, 0), at which point Lua looks at you with a raised eyebrow and proceeds to do...absolutely nothing. 0 isn't a valid table index to Lua, so it doesn't remove your first element.
Change your indices to start at 1 and all should be well:
switchCounter = 1
switchID = {}
--if checkbox-is-checked then
switchID[switchCounter] = checkbox.id
switchCounter = switchCounter + 1
table.sort(switchID)
--elseif checkbox-is-unchecked then
for p = 1, #switchID do
if switchID[p] == checkbox.id then
table.remove(switchID, p)
end
end
switchCounter = #switchID+1
table.sort(switchID)
EDIT: See nobody's excellent remarks below for better information about Lua's stance on indexing.