'DIG' equivalent in LUAplayer?

[Art]

Forgive me if this is obvious, I checked out the tutorial on the LUA
maths library because that's where I expected to find it...

One of my basic compilers provide a maths operation for selecting any
digit of a variable, say digit 2 of 255, and setting another variable to that value.

The syntax would be:
variable1 = variable2 DIG 2

Is there any feature like that in LUAplayer that doesn't use exsessive time?
Cheers, Art.

[KawaGeo]

In order to understand what you meant:

Say, variable1 = 123. What is the result of variable2?

[Art]

That depends on whether you start counting digits from zero or from 1.
But if you started from zero, and started counting from the least signifigant
digit, then digit 2 would be 1, so:

variable1 = 123
variable2 = 0
variable2 = variable1 DIG 2

The result stored in variable2 would now be 1.

[Art]

I can decompile the output of the compiler in question,
that will show me how it is done in RISC assembler
using small operations. That might put me in better stead
to convert it to LUA, or express it better in English :)
Art.

[Shine]

Forgive me if this is obvious, I checked out the tutorial on the LUA
maths library because that's where I expected to find it...

Math is a good start, but there are many ways to implement it, e.g.:

Code: Select all

function dig(number, digit)
	local digitValue = math.pow(10, digit)
	return math.floor(math.mod(number, digitValue) / (digitValue / 10))
end

function dig(number, digit)
	local numberString = tostring(number)
	local index = string.len(numberString) - digit + 1
	return tonumber(string.sub(numberString, index, index))
end

assert(dig(7654, 1) == 4)
assert(dig(7654, 2) == 5)
assert(dig(7654, 3) == 6)
assert(dig(7654, 4) == 7)

[Art]

That's great thanx :)
I'll take the top one because it looks the most like on paper..and it looks shorter too.

102/10 = 10.2 <-- DIG 0 = 2
10/10 = 1.0 <-- DIG 1 = 0
1/10 = 0.1 <-- DIG 2 = 1

I have figured out the syntax to reverse:
var1 = dig(var4, 3)
var2 = dig(var4, 2)
var3 = dig(var4, 1)

Cheers, Art.

[Zenurb]

I think i see a use for this in displaying numbers from a picture font without converting the number to a string. Right?

[Art]

Yes, and it might also come in handy to edit individual digits in an existing number
the way you would need to with a PSP keypad.
Art.