How to change letter to number A=1, B=2?

Other
#1

Is there any easy way to change a letter (from a string) into the corresponding number, such as a=1, b=2, c=3…y=25, z=26 ?

I know I could make a really long if/ifelse that checks for every letter then changes string to specific number, but I feel like this is got to be something that can be done easier.  

#2

Welp, I drafted this up, let me know if there is an easier way. 

local function letterToNumber(letter) local alphabet = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"} local num = 0 for i = 1, 26 do if ( alphabet[i] == letter) then num = i break end end return num end
#3

Hi.

These values should be in order on any sane platform, so you can turn a into a byte, do the same with your current letter, then find the difference. An example iterating over the alphabet:

local alphabet = "abcdefghijklmnopqrstuvwxyz" local A = ("a"):byte() for char in alphabet:gmatch(".") do print(char, char:byte() - A + 1) end

That should be okay for the basic character set, but might need some work if you need more than that.

#4

concur: string.byte

also see string.char (in case you need to go the other way too)

#5

All of the above and many other ways.

#6

Handle upper or lowercase with this where ‘c’ is the character you want a value for:

number = string.byte(string.upper( c )) - 64

#7

 Is this a question or an answer?  I think it is the latter, but I’m just curious.

#8

A simple solution that provides the ordinal value of A-Z or a-z.

#9

Welp, I drafted this up, let me know if there is an easier way. 

local function letterToNumber(letter) local alphabet = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"} local num = 0 for i = 1, 26 do if ( alphabet[i] == letter) then num = i break end end return num end
#10

Hi.

These values should be in order on any sane platform, so you can turn a into a byte, do the same with your current letter, then find the difference. An example iterating over the alphabet:

local alphabet = "abcdefghijklmnopqrstuvwxyz" local A = ("a"):byte() for char in alphabet:gmatch(".") do print(char, char:byte() - A + 1) end

That should be okay for the basic character set, but might need some work if you need more than that.

#11

concur: string.byte

also see string.char (in case you need to go the other way too)

#12

All of the above and many other ways.

#13

Handle upper or lowercase with this where ‘c’ is the character you want a value for:

number = string.byte(string.upper( c )) - 64

#14

 Is this a question or an answer?  I think it is the latter, but I’m just curious.

#15

A simple solution that provides the ordinal value of A-Z or a-z.