[SOLVED] Test if the color exists and how to call [see post]

Hello,

I am creating something ( Its not important what it is :P/> ) that rougly uses this function:

function someFunc( color1, color2, color3 )
	-- How can I check if color1, color2, color3 is a valid color, like cyan
	
	term.setTextColor( colors.color1 )
	print( "Something" )
	
	term.setTextColor( colors.color2 )
	print( "Something again" )
	
	term.setTextColor( colors.color3 )
	print( "Something again, again" )
end

-- This is thought how I would write it, but I dont think it is efficient

function secondFunc( color1, color2, color3 )
	local tColors = { "white", "orange", "magenta", } -- etc
	local col1, col2, col3
	for i = 1, #tColors do
		if color1 == tColors[i] and not col1 then
			color1 = colors. --curr color, not sure how to do this
			col1 = true
		end
		if color2 == tColors[i] and not col2 then
			color2 = colors. --curr color, not sure how to do this
			col2 = true
		end
		if color3 == tColors[i] and not col3 then
			color3 = colors. --curr color, not sure how to do this
			col3 = true
		end
	end
	
	if col1 and col2 and col3 then
		term.setColor( col1 )
		print( "Something" )
		--Everything else from previous function except differnt color vars
		return true
	else
		return false
	end
end

I want to make this more efficient and I dont know how to actually set the color.

Thanks in advance,
Engineer

-- pass just a string color such as 'blue'
if colors[color] then
  print("Color exists")
else
  print("Color does not exist")
end

Alternatively you could loop through the colors table and check each value…

local function checkColor(color)
  for i,v in pairs(colors) do
    if v==color then return true end
  end
  return false
end

function somefunc(...)
  local cols = {...}
  for i =1, #cols do
    cols[i] = colors[cols[i]] or colours[cols[i]]
  end
  return cols
end

Not sure what you're attempting to accomplish with the second function.

Bubba, on 12 March 2013 - 07:39 AM said:

-- pass just a string color such as 'blue'
if colors[color] then
  print("Color exists")
else
  print("Color does not exist")
end

Alternatively you could loop through the colors table and check each value…

local function checkColor(color)
  for i,v in pairs(colors) do
	if v==color then return true end
  end
  return false
end

Thanks, this way I can check if the color exists. Now how do I set it to that specific color?

Lyqyd, on 12 March 2013 - 07:43 AM said:

function somefunc(...)
  local cols = {...}
  for i =1, #cols do
	cols[i] = colors[cols[i]] or colours[cols[i]]
  end
  return cols
end

Not sure what you're attempting to accomplish with the second function.

The second should be checking if the colors exist, and if only all the 3 colors exist then it should do some code involving those colors.
I now know how to check it properly, but I don't know how to set it to the color.

You set it the same way you did to check:

term.setBackgroundColor(colors[color]) -- color is the passed string, like "blue" or "red", etc.

You may want to check in colours too, just in case someone writes grey instead of gray or something:

local col = colors[color] or colours[color]
if not col then
  error("That color doesn't exist!")
end
term.setBackgroundColor(col)

MysticT, on 12 March 2013 - 07:58 AM said:

You set it the same way you did to check:

term.setBackgroundColor(colors[color]) -- color is the passed string, like "blue" or "red", etc.

You may want to check in colours too, just in case someone writes grey instead of gray or something:

local col = colors[color] or colours[color]
if not col then
  error("That color doesn't exist!")
end
term.setBackgroundColor(col)

This pushed me definitely in the right direction.
Than I need the create a table like this:

local tColors = {
  ["gray"] = colors.gray
  [""red"]  = colors.red
  --etc
}

Thanks a lot everyone!

Wait, why? What does that table accomplish that's different than using the colors table?

tColors.gray == colors.gray
tColors["gray"] == colors["gray"]
col = "gray"
tColors[col] == colors[col]

So what's the advantage?

Lyqyd, on 12 March 2013 - 08:42 AM said:

Wait, why? What does that table accomplish that's different than using the colors table?

tColors.gray == colors.gray
tColors["gray"] == colors["gray"]
col = "gray"
tColors[col] == colors[col]

So what's the advantage?

Can you just call colors?

Wow i am such a derp :/

Thanks for pointing that out.

Or you can do it the mathematical way:

function chkColor(color)
  local exp = math.log(color, 2)
  if exp == math.floor(exp) and exp <= 16 then
    return true
  end

  return false
end

I know this is solved, but maybe someone is interesed in it…:D/>

math.log only takes one argument, and returns the natural log, so to get the base 2 log, you have to do log(n)/log(2).

Also, log will give 0 to 15, so your upper condition test should be exp<16 or <=15, and you need to check the lower condition, exp>=0, as well.

Also also, the whole point was to validate strings describing colors, not the numeric values, so your alternative rather misses the original point

GopherAtl, on 12 March 2013 - 11:11 AM said:

math.log only takes one argument, and returns the natural log, so to get the base 2 log, you have to do log(n)/log(2).

math.log(x [, base])
Thats how it's written on the lua documentation, so base should be the base…

GopherAtl, on 12 March 2013 - 11:11 AM said:

[…] and you need to check the lower condition, exp>=0, as well.

Didn't expext anyone to type a float as a color

GopherAtl, on 12 March 2013 - 11:11 AM said:

Also also, the whole point was to validate strings describing colors, not the numeric values, so your alternative rather misses the original point

Yes, and it was already solved, too. That's what I wrote in my post. But still this may be usefull if you pass over the number of the color, you can't always use a string. (Expecially if you have combined colors and you want to filter the colors out, this is the method you want to use)

math.log may take the base in proper lua, but it doesn't in luaj.

JokerRH, on 13 March 2013 - 04:29 AM said:

math.log(x [, base])
Thats how it's written on the lua documentation, so base should be the base…

That's for Lua 5.2, CC uses Lua 5.1. This is the manual for 5.1, math.log just takes one argument.

If you filter against some out-of-range data, you should filter against all out-of-range data, within reason.