lua-table

Hi I'm trying to wrap the following function using SWIG. static void readTable(int argc, t_atom *argv) { //accepts table in Lua e.g. readTable({"ab",3}); for (int i=0; i<argc; ++i) { if (argv[i].a_type == A_FLOAT) printf("FLOAT : %g\n", argv[i].a_w.w_float); else if (argv[i].a_type == A_SYMBOL) printf("SYMBOL : %s\n", argv[i].a_w.w_symbol->s_name); } } Here's the typemap I created. %include "exception.i" %typemap(in) (int argc, t_atom *argv) { if (!lua_istable(L, 1)) { SWIG_exception(SWIG_RuntimeError, "argument mismatch: table expected"); } lua_len(L, 1); $1 = lua_tointeger(L, -1); $2 = (t

I'm learning Lua for corona sdk and I have these local type1 = {nil, "(", nil, "x" ,nil , ")" ; n=6} local type2 = {"(",nil, "x",nil, ")",nil ; n=6} print(#type1) --prints 6 print(#type2) --prints 3 why the second one is not 6 too?? The # operator doesn't work on every table, it works only on a sequence, that is, the set of its positive numeric keys is equal to {1..n} for some integer n . In that case, n is its length. For instance, local t = {"hello", 42, true} is a sequence. But both your tables are not sequence because they have "holes" of nil . See Lua 5.2 Reference Manual: The length

Is there any way to loop trough a table like the one below in the same order as it's written? local tbl = { ["hello"] = 1, [2] = 2, [50] = 3, ["bye"] = 4, [200] = 5 } What I mean is that when I use "in pairs" I'll get a different order everytime I execute my code ... I'm searching for something like this: function get_keys(tbl) local rtable = {} for k,v in pairs(tbl) do table.insert(rtable, k) end return rtable end local keys_of_tbl = get_keys(tbl) for i = 1, table.getn(keys_of_tbl) do --Do something with: tbl[keys_of_tbl[i]] end But because the function "get_keys" is based on "in pairs" again

Writing a function in Lua, which creates two tables. I want the tables to be assigned to the value name with an x added, and one with a y added. For example if name was line, it would create two tables linex and liney, but I can't figure out how to do it. The following obviously doesn't work (and is just for display purposes) but how would I go about doing this? function makelinep(x,y,minrand,maxrand,name,length) name..x = {} name..y = {} Later I hope to access "linex" and "liney" after values have been written. Joel If you want these in the global name space you would use _G[name..'x']={} _G

i am having a table in lua test = {1,2,4,2,3,4,2,3,4,"A", "B", "A"} I want to remove all duplicate elements in table. Output should be test = {1,2,4,3,"A","B"} EDIT: My try : > items = {1,2,4,2,3,4,2,3,4,"A", "B", "A"} > flags = {} > for i=1,table.getn(items) do if not flags[items[i]] then io.write(' ' .. items[i]) flags[items[i]] = true end >> end 1 2 4 3 A B> It is working fine now. Thanks for answers and comments. Similar to example given by @Dimitry but only one loop local test = {1,2,4,2,3,4,2,3,4,"A", "B", "A"} local hash = {} local res = {} for _,v in ipairs(test) do if (not hash[v])

This question already has an answer here: Lua unpack() messing arguments 1 answer Could somebody explain to me why table.unpack() returns the first table element only when it is used in a function call with additional parameters after table.unpack() ? Here is some demo code: local a = {1,2,3,4,5} print("Test", table.unpack(a)) -- prints "Test 1 2 3 4 5" print(table.unpack(a), "Test") -- prints "1 Test" I don't understand why the second line just prints 1 Test . I'd expect it to print 1 2 3 4 5 Test . Can somebody explain this behaviour? I'd also be interested in how I can make the second call

In my main coroutine, I am removing or adding entries from a table depending on user operations. In the background, I'd like to iterate over the entries in the table. I don't mind particularly if I miss an insertion on one iteration, providing I can catch it before the next. Is it safe to iterate over it with pairs ? Or should I use next instead? You can safely remove entries while traversing a table but you cannot create new entries, that is, new keys. You can modify the values of existing entries, though. (Removing an entry being a special case of that rule.) JUST MY correct OPINION You can