Re: split method?

On Mon, Jun 27, 2011 at 6:37 PM, Dave Collins <Dave.Collins@mercatustechnologies.com> wrote:

I’ve used this split (string to table) method I found here: http://stackoverflow.com/questions/1426954/split-string-in-lua.

This is our split function:

function split(s, sep)

local res = {}

sep = sep or ' '

for v in s:gmatch('[^' .. sep .. ']+') do

res[#res + 1] = v

end

return res

end

Usage:

t=split("2011-06-21","-")

> for k,v in pairs(t) do print(k,v) end

1 2011

2 06

3 21

best regards,

Valerio

I’ve got it working, but I don’t understand it.

function string:split(delimiter)

      local result = { }
      local from = 1
      local delim_from, delim_to = string.find( self, delimiter, from )

      while delim_from do
            table.insert( result, string.sub( self, from , delim_from-1 ) )
            from = delim_to + 1
            delim_from, delim_to = string.find( self, delimiter, from )

      end
      table.insert( result, string.sub( self, from ) )
      return result

end

This is how I’m calling it:

local myDateString = "2011-06-21"

local myDateTbl = myDateString.split(myDateString,"-")

dump_table(myDateTbl)

1=2011
2=06

3=21

Two things I don’t understand:

1] When I call it, I reference it twice: myDateString.split(myDateString,"-")Why? Or should I just do this: string.split(myDateString,"-") Which works, so I guess the answer is yes.

2] The function takes one parameter (delimiter), but I must pass it two (myDateString, "-"). If I only pass it the delimiter string like it seems to want, it breaks. Why does it take two when it looks like it takes one?

Are these both occurring because I’m not really writing a function, I’m really modifying the string prototype?

Dave Collins
Front-End Engineer

Mercatus Technologies Inc.
60 Adelaide Street East, Suite 700
Toronto ON M5C 3E4
T 416 603 3406 x 298
F 416 603 1790

dave.collins@mercatustechnologies.com

www.mercatustechnologies.com