Lua Csv

wiki

• Programming in Lua - [1] - has example code for parsing CSV files.
• The Lpeg library - [2] - also has example code for parsing CSV files.
• [LuaCSV] is a C module for reading CSV
• CsvUtils - some utility functions
• The Lua Unofficial FAQ, has an entry "How to read CSV data?" [3]

Parser in Lua

A simple parser for comma-separated-value (.csv) files:

function ParseCSVLine (line,sep) 

	local res = {}

	local pos = 1

	sep = sep or ','

	while true do 

		local c = string.sub(line,pos,pos)

		if (c == "") then break end

		if (c == '"') then

			-- quoted value (ignore separator within)

			local txt = ""

			repeat

				local startp,endp = string.find(line,'^%b""',pos)

				txt = txt..string.sub(line,startp+1,endp-1)

				pos = endp + 1

				c = string.sub(line,pos,pos) 

				if (c == '"') then txt = txt..'"' end 

				-- check first char AFTER quoted string, if it is another

				-- quoted string without separator, then append it

				-- this is the way to "escape" the quote char in a quote. example:

				--   value1,"blub""blip""boing",value3  will result in blub"blip"boing  for the middle

			until (c ~= '"')

			table.insert(res,txt)

			assert(c == sep or c == "")

			pos = pos + 1

		else	

			-- no quotes used, just look for the first separator

			local startp,endp = string.find(line,sep,pos)

			if (startp) then 

				table.insert(res,string.sub(line,pos,startp-1))

				pos = endp + 1

			else

				-- no separator found -> use rest of string and terminate

				table.insert(res,string.sub(line,pos))

				break

			end 

		end

	end

	return res

end