How to insert data and tables into an existing one? - lua

Question

I have a trouble inserting new rows and tables into an already existing one.
Lets call the source SourceFile.lua and its simplified contents:
SourceFile = {};
SourceFile.list = {
BrandName1 = {
number = 10,
products = {
"Product1", 3,
"Product2", 4,
"Product3", 7,
},
},
BrandName2 = {
number = 5,
products = {
"Product1", 10,
"Product2", 3,
"Product3", 6,
},
},
-- and so on
}
I want to do something like this:
require 'SourceFile'
local myData = {
BrandName2 = { -- add new products for the existing brand
products = {
"Product4", 2,
},
},
MyBrandName1 = { -- add new brand
number = 12,
products = {
"MyProduct1", 21,
"MyProduct2", 95,
},
},
-- and so on
}
table.insert(SourceFile.list, myData)
However there's something wrong in my code and I get the following result (printed with inspect):
{
list = { {
BrandName2 = {
products = { "Product4", 2 }
},
MyBrandName1 = {
number = 12,
products = { "MyProduct1", 21, "MyProduct2", 95 }
}
},
BrandName1 = {
number = 10,
products = { "Product1", 3, "Product2", 4, "Product3", 7 }
},
BrandName2 = {
number = 5,
products = { "Product1", 10, "Product2", 3, "Product3", 6 }
}
}
}
What am I doing wrong?
I'm new to lua and pretty sure that it's something obvious, but not for me. Please, help me.
Addition
After these answers I've also found a way to insert new brand names one by one:
SourceFile.list.MyBrandName1 = {
number = 12,
products = {
"MyProduct1", 21,
"MyProduct2", 95,
},
}
This does not fully answer my question, but might be useful to someone new to lua.

Answer 1

table.insert adds its second argument to an array (its first argument). Your SourceFile.list is only supposed to have string keys, so it can't work as an array. You'll need a recursive function to merge the data from one table into the other:
local function meld(data, newData)
for k, v in pairs(newData) do
local oldValue = data[k]
if type(oldValue) ~= 'table' or type(v) ~= 'table' then
-- One of the values is not a table, so let's clobber the old value.
data[k] = v
else
-- Both are tables.
meld(oldValue, v)
end
end
end
meld(SourceFile.list, myData)

Answer 2

You are pushing a table of brandnames into a list of brandnames.
Which makes it a list of brandnames + table with brandnames.
table.insert(SourceFile.list, myData)
This inserts myData to SourceFile.list. myData is a table with brandnames.
SourceFile.list is also a table with brandnames.
List in list.
You have 2 choices to solve this:
Insert each brandname separately
Make a function to merge contents of myData to SourceFile.list