Lua - Getting values from nested tables

Question

Okay so I have been searching everywhere for this, but nowhere has the answer.

I have a nested table (an example):

{
  {
    "Username",
    "Password",
    "Balance",
  },
  {
    "username1",
    "password1",
    1000000,
  },
  {
    "username2",
    "password2",
    1000000,
  },
}

The thing is I can't iterate a loop to view these tables, nor get values from the tables. None nested tables can be accessed easily like:

print(a[1])

How do I loop them and get values from them?

What happens when you do `print(a[1])`? Did you try `print(a[1][1])`? — Tom Blodget, Jul 07 '14 at 16:48

score 4 · Accepted Answer · edited Jul 07 '14 at 01:29

4

Use pairs or ipairs to iterate over the table:

local t = {
  {
    "Username",
    "Password",
    "Balance",
  },
  {
    "username1",
    "password1",
    1000000,
  },
  {
    "username2",
    "password2",
    1000000,
  },
}

for _, v in ipairs(t) do
  print(v[1], v[2],v[3])
end

will print:

Username    Password    Balance
username1   password1   1000000
username2   password2   1000000

edited Jul 07 '14 at 01:29

hugomg

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answered Jul 06 '14 at 19:35

Paul Kulchenko

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I think in this case ipairs is a better choice – hugomg Jul 06 '14 at 19:35

score 3 · Answer 2 · answered Jul 06 '14 at 19:34

If you have

a =  {
   { "Username", "Password", "Balance", },
   { "username1", "password1", 1000000, },
   { "username2", "password2", 1000000, },
}

Then the second element of a will be a[2], the table { "username1", "password1", 1000000, }. If hyou print it it will look similar to table: 0x872690 - its just just how tables are printed in Lua by default. To access the inner fields you just use the same indexing operators. For the first field we do a[2][1], for the second we do a[2][2] and so on.

 for i = 2, #a do
     print(a[i][1], a[i][2], a[i][3])
 end

Lua - Getting values from nested tables

2 Answers2