Delete JPGs that don't have a matching raw file

gistfile1.lua

lfs = require "lfs"
local sPath = 'D:/temp photos/'

function hasExtension ( sFilename, sExt )
    if sFilename then
        return string.match ( string.lower ( sFilename ), "." .. string.lower( sExt ) ) ~= nil
    end

    return false
end

function getFileNameAndExtension ( sFilename )
	if sFilename then
		-- match (anything not a .).(anything not a .)
		for k, v in string.gmatch ( sFilename, "([^\.]+)\.([^\.]+)" ) do
			return k, v
		end
	end

	return nil, nil
end

function file_exists(name)
   local f=io.open(sPath .. name,"r")
   if f~=nil then io.close(f) return true else return false end
end


local nJpg = 0
local nRAW = 0
local nMissingRaws = 0
local nMissingJPGS = 0
local nOther = 0

for file in lfs.dir(sPath) do
    local sName, sExt = getFileNameAndExtension ( file )
    if sExt ~= nil then
        if hasExtension ( file, "jpg" ) then
            nJpg = nJpg + 1
            if not file_exists ( sName .. ".CR2" ) then
                nMissingRaws = nMissingRaws + 1
            end
        elseif hasExtension ( file, "cr2" ) then
            nRAW = nRAW + 1

            if not file_exists ( sName .. ".JPG" ) then
                nMissingJPGS = nMissingJPGS + 1
                --print ( "Delete ", file )
                os.remove ( sPath .. file )
            end
        else
            nOther = nOther + 1
        end
    end
end

print("Found JPG: ", nJpg)
print("Found RAW: ", nRAW)
print("Found other: ", nOther)
print("Total: ", (nJpg + nRAW + nOther))
print ( "Missing JPG: ", nMissingJPGS )
print ( "Missing RAW: ", nMissingRaws )