Multidimensional Arrays via ajax to PHP - php

Question

Ok seriously struggling here. I am having some problems trying to send a multdimensional array to PHP via ajax. Here's what I have been trying:
To simplify rather than copy paste a wall of code:
peoplearray[0] = [name] => 'john'
[age] => '28'
[sex] => 'Male'
peoplearray[1] = [name] => 'julie'
[age] => '20'
[sex] => 'Female'
main_array['item'] = 'x';
main_array['something'] = 'x';
main_array['another'] = 'x';
I want to get this to php via post. I figured I may aswell just join them together as I am multidimensional anyway thus :
main_array['peoplearray'] = peoplearray;
now to do the ajax:
// var data = JSON.stringify(main_array);
var send = $.ajax({
type: "POST",
cache: false,
url: "theurl",
data: {data:main_array} //I do change this `main_array` when using the above stringify!
});
send.done(function(msg) {
console.log(msg);
})
in PHP I am just doing the following right now:
$data= $_POST['data'];
print_r($data);
in firebug: (an empty string)
when I have the var data = JSON.stringify(main_array); uncommented I get the following: [][
if i add $data = json_decode($_POST['data']); to the php I get:
Array ( )
Basically the main_array I realise does not need to be an array and so I can get that stuff across no problem but what I need to do is get the peoplearray over so that I can do some foreach etc... with it in php. Any help would be much appreciated I am sure I am just being stupid!
EDIT: The reasoning behind this is that peoplearray could have 0 or 100 entries so I just need to get it to php so I can foreach it to do the DB inputs. If there is a better approach I would be very grateful to hear it as I am still pretty new to this.
EDIT: Thanks to Nicola's answer everything is passing fine except the important part which is mainarry.peoplearray - it is not appearing in the the return console.log and I cant access it in PHP. Any solutions on this or do I have to put the foreach intelligence in the javascript and just send everything individually?

Answer 1

First of all main_array is not an array but an object because in javascript there are no associative arrays and for this reason
main_array['peoplearray'] = peoplearray;
is equivalent to
main_array.peoplearray = peoplearray;
and you should declare main_array like this
var main_array = {};
then try to change your function like this:
var send = $.ajax({
type: "POST",
dataType: "json",
cache: false,
url: "theurl",
data: {data:main_array}
});
and server side
header('Content-type: application/json');
$data= $_POST['data'];
echo json_encode($data);

Answer 2

I got it to work by keeping the peoplearray seperate.
So I did as Nicola said and created mainarray as an object ie. declaring with curlies: {}
The peoplearray I left as an array ie declaring with [], however then name,age&sex fields I created as an object ie. {} and then .push() them into the the peoplearray.
Then the ajax looked as follows:
var send = $.ajax({
type: "POST",
dataType: "json",
cache: false,
url: "theurl",
data: {data:main_array, people:peoplearray}
});
then with the PHP everything is available in the $_POST, and if you
echo json_encode($people); //or whatever var name it is stored as in the php
the objects ie name,age,sex properties are shown in the
send.done(function(msg) {
console.log(msg);
})