Changing number as a word to the number value - lua

Question

I am trying to change a string that is the word for a number between one and fifty to the number value, i.e. if
local = "twelve" it will make local_num = 12, if local = "one" then local_num = 1, etc. Do I just use an array and loop a compare?

Answer 1

There is no need for a loop. Just use this table directly:
Word2Number={
["zero"]=0,
["one"]=1,
["two"]=2,
["three"]=3,
["four"]=4,
["five"]=5,
["six"]=6,
["seven"]=7,
["eight"]=8,
["nine"]=9,
["ten"]=10,
["eleven"]=11,
["twelve"]=12,
["thirteen"]=13,
["fourteen"]=14,
["fifteen"]=15,
["sixteen"]=16,
["seventeen"]=17,
["eighteen"]=18,
["nineteen"]=19,
["twenty"]=20,
["twenty-one"]=21,
["twenty-two"]=22,
["twenty-three"]=23,
["twenty-four"]=24,
["twenty-five"]=25,
["twenty-six"]=26,
["twenty-seven"]=27,
["twenty-eight"]=28,
["twenty-nine"]=29,
["thirty"]=30,
["thirty-one"]=31,
["thirty-two" ]=32,
["thirty-three" ]=33,
["thirty-four"]=34,
["thirty-five"]=35,
["thirty-six"]=36,
["thirty-seven"]=37,
["thirty-eight"]=38,
["thirty-nine"]=39,
["forty"]=40,
["forty-one"]=41,
["forty-two"]=42,
["forty-three"]=43,
["forty-four"]=44,
["forty-five"]=45,
["forty-six"]=46,
["forty-seven"]=47,
["forty-eight"]=48,
["forty-nine"]=49,
["fifty"]=50,
}

Answer 2

This is the code to spell an integer
local append, concat, floor, abs = table.insert, table.concat, math.floor, math.abs
local num = {'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten', 'eleven',
'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen'}
local tens = {'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety'}
local bases = {{floor(1e18), ' quintillion'}, {floor(1e15), ' quadrillion'}, {floor(1e12), ' trillion'},
{floor(1e9), ' billion'}, {1000000, ' million'}, {1000, ' thousand'}, {100, ' hundred'}}
local insert_word_AND = false -- 101 = "one hundred and one" / "one hundred one"
local function IntegerNumberInWords(n)
-- Returns a string (spelling of integer number n)
-- n should be from -2^53 to 2^53 (-2^63 < n < 2^63 for integer argument in Lua 5.3)
local str = {}
if n < 0 then
append(str, "minus")
end
n = floor(abs(n))
if n == 0 then
return "zero"
end
if n >= 1e21 then
append(str, "infinity")
else
local AND
for _, base in ipairs(bases) do
local value = base[1]
if n >= value then
append(str, IntegerNumberInWords(n / value)..base[2])
n, AND = n % value, insert_word_AND or nil
end
end
if n > 0 then
append(str, AND and "and") -- a nice pun !
append(str, num[n] or tens[floor(n/10)-1]..(n%10 ~= 0 and '-'..num[n%10] or ''))
end
end
return concat(str, ' ')
end
And this is how to use it:
local function digitize(number_as_text)
number_as_text = number_as_text:lower():gsub("%W", "")
for i = 1, 50 do
if IntegerNumberInWords(i):lower():gsub("%W", "") == number_as_text then
return i
end
end
end
print(digitize(io.read()))