How can I convert a string to binary numbers?

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#1

Hi,
I need to write a function that will convert string to binary numbers, for example if I have a string "hello" then according to ASCII its binary substitute is 01101000 01100101 01101100 01101100 01101111 (Ascii Text to Binary Converter), I think that bit32 library would be helpful. Can someone help me write this function?

local function stringToBinNumber(str)
    local binarySubstitute
    -- ???
    return binarySubstitute
end
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#2

lua has a built in function to get the numerical representation of a character:

string.byte(str: string, index: number = 1) -> (number)

you can then manually write a function to convert said number to binary by using modulus and repetition. You could probably find something like that on stackoverflow

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#3

Not sure if this works but you can try:

local function stringToBinNumber(str)
    local res = ""
    for letter in pairs(str:split("")) do
        local byte = letter:byte()

        res ..= "0" .. convert(byte) .. " "
    end
    return res
end
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#4

actually, using bit32 you could do something like this

local binaryNum = ""
for i = 8, 1, -1 do
	local temp = if bit32.band(num, 2^i) == 0 then 0 else 1
	binaryNum = binaryNum .. temp
end
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#5

this might be scuffed but I tested it and it looks like it works:

local function convert(num: number, bits: number): (string)
	local binaryNum = ""
	for i = bits - 2, 0, -1 do
		local temp = if bit32.band(num, 2^i) == 0 then 0 else 1
		binaryNum ..=  temp
	end
	return binaryNum
end

local function stringToBinNumber(str: string, bits: number): (string)
	local res = ""
	for _, letter in ipairs(str:split("")) do
		local byte = letter:byte()

		res ..= "0" .. convert(byte, bits) .. " "
	end
	return res
end
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#6

Oops, I forgot the concert function lol. I had something in mind but since it’s solved I won’t waste brain power lol

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#7

Joshument’s solution is flawless, but I’d like to share a shorter solution

local function stringToBinary(str)
    return str:gsub(".", function(character)
        local result = ""
        for bit_index = 0, 7 do
            result ..=  bit32.extract(str:byte(), bit_index) -- extract will return the bit at the (bit_index+1)the position
        end
        return result .. " "
    end):sub(1, -2) -- to remove the extra space at the end
end
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#8

Oh cool, had no idea that bit32.extract() existed, thanks for sharing!

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#9

For me it returns 00101010 for every character

#10

Oh my bad, I meant character:byte() insted of str:byte(). It’s the same for all because it based the bits off of the original string3

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#11

The return values aren’t correct. If I want to translate “hello” your script returns this:
00010110 10100110 00110110 00110110 11110110
but it should be like this:
01101000 01100101 01101100 01101100 01101111

Edit: Wait, isn’t it reversed?

#12

Yeah seems like it, another mistake, supposed to be 7, 0, -1 instead. I didn’t test the code so no wonder it’s this broken.

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