lua-table

I'm going to implement a function with C language and which will be called by Lua script. This function should receive a lua table as the argument, so I should read the fields in the table.I try to do like below, but my function is crashing when I run it. Can anyone help my find the problem? /* function findImage(options) imagePath = options.imagePath fuzzy = options.fuzzy ignoreColor = options.ignoreColor; end Call Example: findImage {imagePath="/var/image.png", fuzzy=0.5, ignoreColor=0xffffff} */ // implement the function by C language static int findImgProxy(lua_State *L) { luaL_checktype(L

I'm new to Lua, and I'm learning the usage of table these days. From tutorials I know that Lua treats numeric indexed items and non-numeric indexed items differently, so I did some tests myself, and today I found an interesting phenomenon and I can't explain it: The code t = {1, 2, 3, a='a', b='b'} print(#t) gets 3 because the # operator counts numeric indexed items only. Then I tested the following code t = {1, 2, 3, a='a', b='b'} print(#t) for i = 100,200 do t[i] = i end print(#t) I get 3 3 Till now I think Lua treats those discontinuous items added later as non-numeric indexed ones. However

Is there a method for checking if a table contains a value ? I have my own (naive) function, but I was wondering if something "official" exists for that ? Or something more efficient... function table.contains(table, element) for _, value in pairs(table) do if value == element then return true end end return false end By the way, the main reason I'm using this functions is to use tables as sets, ie with no duplicate elements. Is there something else I could use ? interjay You can put the values as the table's keys. For example: function addToSet(set, key) set[key] = true end function

How can I get the data which is a table inside a table, i mean like this: t = { {a, b, c}, {d, e, f} }; if I write this line of code: print( t[1] ) the result will be —–>>> {a, b, c} BUT how can I print just the letter “a”? without using ipairs I mean is there any way to use something like t[1] ? Have you tried t[1][1] ? That should get you the first index in the table you get from t[1] 来源： https://stackoverflow.com/questions/6807969/table-inside-table-in-lua

I have really Googled this question but I never really got an solution. I want to share an Array between C and Lua, for performance I will avoid copying Arrays to and from Lua. So I want to pass a pointer to the Array from C to Lua. And then from Lua I want to set/modify values in this array directly. Example in C code I want to define my array int mydata[] = {1,2,3,4} set it global to access it from Lua with the name mydata . In Lua I want to change the values like this mydata[3] = 9 and when I return to C, mydata[3] is 9 because it is a pointer to the array. How is this possible? You can

I am trying to iterate through a lua table but I keep getting this error: invalid key to 'next' I know that index starts off as -8 and I know that there is a table there because it gets the first (and only) value in it. However, it tries to loop round again even though I know there is only one string in the table. if (lua_istable(L, index)) { lua_pushnil(L); // This is needed for it to even get the first value index--; while (lua_next(L, index) != 0) { const char *item = luaL_checkstring(L, -1); lua_pop(L, 1); printf("%s\n", item); } } else { luaL_typerror(L, index, "string table"); } Any help