Break a string to table

Question

Currently, I am using this function:

function tokenize( str )
  local ret = {}
  string.gsub( str, "([-%w%p()%[%]®+]+)", function( s ) table.insert( ret, s ) end )
  return ret
end

Now, the string can have any character in it(as is clear from function above). I want to break the string to words detecting only the white-spaces and no other character. I have seen the solution mentioned here but it is not helping me even on codepad.org (link). I am working in PtokaX, in case you are wondering. I have tried using

print( split( 'foo/bar/baz/test','/' ) )

too, but that doesn't work either. :(

Is there any other easier way to create the table?

score 2 · Accepted Answer · answered Mar 22 '12 at 13:33

Why don't you just match for non space characters, instead of matching all others?

function tokenize( str )
  local ret = {}
  string.gsub( str, "(%S+)", function( s ) table.insert( ret, s ) end )
  return ret
end

If you want to use other characters for splitting, the pattern set negation is also useful:

s='foo#bar!baz*'
s:gsub('([^#!%*]+)',function(s) print(s) end)

See also: Patterns in the Lua Manual. Also keep in mind Lua patterns are not the same as regexes, they are lighter, but have their limitations.

score 1 · Answer 2 · answered Mar 23 '12 at 02:22

If you will be working with more advanced structures, I recommend LPeg.

require"lpeg"
lpeg.locale(lpeg)

local pattern = lpeg.P(
    lpeg.Ct(
        (lpeg.space^0*lpeg.C(-lpeg.space)^1)^0
    )
)

local ret = lpeg.match(pattern, str)

for k,v in ipairs(ret) do
    print(k, v)
end

Break a string to table

2 Answers2