Convert hex to decimal keeping fractional part in Lua
- by Zack Mulgrew
Lua's tonumber function is nice but can only convert unsigned integers unless they are base 10. I have a situation where I have numbers like 01.4C that I would like to convert to decimal.
I have a crummy solution:
function split(str, pat)
local t = {}
local fpat = "(.-)" .. pat
local last_end = 1
local s, e, cap = str:find(fpat, 1)
while s do
if s ~= 1 or cap ~= "" then
table.insert(t,cap)
end
last_end = e+1
s, e, cap = str:find(fpat, last_end)
end
if last_end <= #str then
cap = str:sub(last_end)
table.insert(t, cap)
end
return t
end
-- taken from http://lua-users.org/wiki/SplitJoin
function hex2dec(hexnum)
local parts = split(hexnum, "[\.]")
local sigpart = parts[1]
local decpart = parts[2]
sigpart = tonumber(sigpart, 16)
decpart = tonumber(decpart, 16) / 256
return sigpart + decpart
end
print(hex2dec("01.4C")) -- output: 1.296875
I'd be interested in a better solution for this if there is one.
