[Retracted] Syntax question - are these two things 'the same' ? [No they aren't]

I'm trying to learn new and better ways of doing things so I recently tried replacing

if newSettings.outputType == "A" or newSettings.outputType == "D" then

with

if newSettings.outputType == ("A" or "D") then

It seems to work but before I start relying on this new 'technique' my question remains: are these two functionally equivalent and can I rely on either to produce the same results?

EDIT:
After further experimentation I've found that they aren't the same and I am still somewhat boggled at the many possible uses of 'and' and 'or'.

They are indeed not the same.

if newSettings.outputType == ("A" or "D") then

is the same as

if newSettings.outputType == ("A")

Since or simply checks if it's a valid value(not nil or false). If it is, the subsequent values are discarded.

Thanks, CometWolf :)/> If you're so inclined, is there a 'better' or even another way to do this?

if newSettings.outputType == "A" or newSettings.outputType == "D" then

Dog, on 06 April 2014 - 12:30 AM said:

Thanks, CometWolf :)/> If you're so inclined, is there a 'better' or even another way to do this?

if newSettings.outputType == "A" or newSettings.outputType == "D" then

Dog, on 06 April 2014 - 12:30 AM said:

Thanks, CometWolf :)/> If you're so inclined, is there a 'better' or even another way to do this?

if newSettings.outputType == "A" or newSettings.outputType == "D" then

No, I don't think there is. That's a pretty good way of doing it.

When it comes down to so few variables checks, not really. An alternative when you have to deal with a lot, is to use tables.

local valid = {
  A = true,
  D = true
}
if valid[newSettings.outputType] then

CometWolf, on 06 April 2014 - 12:58 AM said:

When it comes down to so few variables checks, not really. An alternative when you have to deal with a lot, is to use tables.

local valid = {
  A = true,
  D = true
}
if valid[newSettings.outputType] then

I had a sneaky feeling tables might be a way of doing it, but I couldn't see how to do it effectively - thanks for the example :)/>

When checks start getting a bit complex, in some cases it pays to relegate them off into functions. For eg, say you want to know if a given key event represents one out of a number of keys, you might do:

local myEvent = {os.pullEvent()}

if myEvent[1] == "key" and (myEvent[2] == keys.up or myEvent[2] == keys.w or myEvent[2] == keys.space or myEvent[2] == keys.enter) then

… or, you might make a dedicated key-checking function:

local myEvent

local function pressedKey(...)
  if myEvent[1] ~= "key" then return false end

  local args = {...}
  for i=1,#args do if args[i] == myEvent[2] then return true end end
  return false
end

myEvent = {os.pullEvent()}

if pressedKey(keys.up,keys.w,keys.space,keys.enter) then

Of course, the benefit depends on how often you're going to make checks of that type.

I boggle at the myriad ways things can be approached in Lua. I'm going to have to give these examples some play time. Thanks, Bomb Bloke, CometWolf, and Agoldfish!