Re: How to find out whether there is a specific key for a given Lua table besides traversing the whole table?

[孙世龙 sunshilong <sunshilong369@...>]

>Assuming table is at index 1
Index 1?
In general, the index of the stack is a negative number, e.g -1, -2, and so on.

On Thu, Jan 14, 2021 at 10:11 PM Roberto Ierusalimschy
<roberto@inf.puc-rio.br> wrote:
>
> > One more way with lua_isnil.
> >
> > lua_pushstring(L, "key");
> > lua_rawget(L, 1); // Assuming table is at index 1
> > if (lua_isnil(L, -1)) {
> >     // It's nil
> > } else {
> >     // It's something else
> > }
>
> Or else:
>
>   lua_pushstring(L, "key");
>   if (lua_rawget(L, 1) == LUA_TNIL) {  // Assuming table is at index 1
>       // It's nil
>   } else {
>       // It's something else
>   }
>
> -- Roberto