1
local array = {1, nil, 2}
2
print(#array)

1
local array = {5, nil, "红酱自动机", 6, 7, 8}
2
print(#array)

1
do
2
    local table = {
3
        [false] = "false",
4
        [true] = "true",
5
        [1] = "one",
6
        [2] = "two",
7
        [3] = "three",
8
        name = "张三",
9
        age = 18,
10
        friend = {
11
            name = "李四",
12
            age = 20
13
        }
14
    }
15
    for k, v in pairs(table) do
16
        print(k, v)
17
    end
18
    print("-------------")
19
    for k, v in ipairs(table) do
20
        print(k, v)
21
    end
22
    print("-------------")
23
    print(#table) -- 3
24
end

1
false   false
2
true    true
3
2       two
4
3       three
5
name    张三
6
friend  table: 0000000000fba550
7
age     18
8
1       one
9
-------------
10
1       one
11
2       two
12
3       three
13
-------------
14
3

1
[1] = "one",
2
[2] = "two",
3
[3] = "three",

1
int luaH_next (lua_State *L, Table *t, StkId key) {
2
  unsigned int asize = t->asize;
3
  unsigned int i = findindex(L, t, s2v(key), asize);  /* find original key */
4
  for (; i < asize; i++) {  /* try first array part（数组区遍历） */
5
    lu_byte tag = *getArrTag(t, i);
6
    if (!tagisempty(tag)) {  /* a non-empty entry? */
7
      setivalue(s2v(key), cast_int(i) + 1);
8
      farr2val(t, i, tag, s2v(key + 1));
9
      return 1;
10
    }
11
  }
12
  for (i -= asize; i < sizenode(t); i++) {  /* hash part（哈希区遍历） */
13
    if (!isempty(gval(gnode(t, i)))) {  /* a non-empty entry? */
14
      Node *n = gnode(t, i);
15
      getnodekey(L, s2v(key), n);
16
      setobj2s(L, key + 1, gval(n));
17
      return 1;
18
    }
19
  }
20
  return 0;  /* no more elements */
21
}

1
/*
2
** Insert a key in a table where there is space for that key, the
3
** key is valid, and the value is not nil.
4
*/
5
static void newcheckedkey (Table *t, const TValue *key, TValue *value) {
6
  unsigned i = keyinarray(t, key);
7
  if (i > 0)  /* is key in the array part? */
8
    obj2arr(t, i - 1, value);  /* set value in the array */
9
  else {
10
    int done = insertkey(t, key, value);  /* insert key in the hash part */
11
    lua_assert(done);  /* it cannot fail */
12
    cast(void, done);  /* to avoid warnings */
13
  }
14
}

1
do
2
    local table = {
3
        "one",
4
        "two",
5
        "three",
6
        [false] = "false",
7
        [true] = "true",
8
        name = "张三",
9
        age = 18,
10
        friend = {
11
            name = "李四",
12
            age = 20
13
        }
14
    }
15
    for k, v in pairs(table) do
16
        print(k, v)
17
    end
18
    print("-------------")
19
    for k, v in ipairs(table) do
20
        print(k, v)
21
    end
22
    print("-------------")
23
    print(#table) -- 3
24
end

1
1       one
2
2       two
3
3       three
4
false   false
5
true    true
6
age     18
7
name    张三
8
friend  table: 0000000000eca1d0
9
-------------
10
1       one
11
2       two
12
3       three
13
-------------
14
3