how to insert an array in another one?

Question

This is an index (of module services) I created a resource that index books on a home page of a mobile app( this is not the most important in my question) I want to get books that have same tid (from table taxonomy) and put them on an array ($livres) at this time when I return $livres it's ok, books are grouped well and no duplications, but after putting them on array $livres, i want to put the $livres on the array $sections, sections contain the "header" that is the name of the section, and the array $livres of every section : the result i want is : [ { 'section' : 'A', 'livres':[{'id_book' : '1','title':'great book'},{'id_book' : '2','title':'great book too'}]},{'section':'B','livres':[{...ect

function my_module_home_index(){
$sections = array();
$livres = array();

$home_livre = db_query("SELECT tax.name as section,field_categorie_tid as tid,field_title_value as titre ,field_prix_value as prix ,t.entity_id FROM {field_data_field_title} as t
    join {field_data_field_prix} as pr on pr.entity_id = t.entity_id
    join {field_data_field_categorie} as cat on cat.entity_id = t.entity_id
    left join {taxonomy_term_data} as tax on tax.tid = cat.field_categorie_tid
    ")->fetchAll();

foreach($home_livre as $book){
    if(!isset($livres[$book-> tid]))
    $livres[$book-> tid] = array();


    $livres[$book->tid][]= array(
        'id_livre'=>$book-> entity_id,
        'titre' => $book-> titre,
        'prix'=> $book-> prix
    );
    $sections[]= array(
        'categorie'=> $book-> section
        'livre'=> $livres[$book->tid]
    );
}       
return $sections;   
  }

This is a part of what postman returns :

{
"categorie": "A",
"livre": [
  {
    "id_livre": "109",
    "titre": "F",
    "prix": "4"
  }
]
  },
{
  "categorie": "A",
  "livre": [
    {
     "id_livre": "109",
    "titre": "F",
    "prix": "4"
  },
  {
    "id_livre": "110",
    "titre": "G",
    "prix": "43"
  }
 ]
},
{

"categorie": "A",
"livre": [
  {
    "id_livre": "109",
    "titre": "F",
    "prix": "4"
  },
  {
    "id_livre": "110",
    "titre": "G",
    "prix": "43"
  },
  {
    "id_livre": "111",
    "titre": "H",
    "prix": "6"
  }
  ]
 },

As you can see; Book number 109 appears every iteration of foreach, how to avoid that ?

This is what return $livres shows (just a part, whent tid : 41, array is grouping all books with this tid so it's ok):

"41": [
{
  "id_livre": "109",
  "titre": "F",
  "prix": "4"
},
{
  "id_livre": "110",
  "titre": "G",
  "prix": "43"
},
{
  "id_livre": "111",
  "titre": "H",
  "prix": "6"
},
{
  "id_livre": "115",
  "titre": "L",
  "prix": "4"
},
{
  "id_livre": "118",
  "titre": "O",
  "prix": "5"
}
  ]
  }

Thank you

EDIT : this is the result postman returns when i "range" the query with 0,5 : i want 5 books (livres) in every sections, did anyone knows how to range the first array (not the second one that contains livres)

"response": [
{
  "section": "roman policier",
  "id_section": "31",
  "livres": [
    {
      "couverture": "http://localhost/drupal/sites/default/files/Etude_en_rouge.jpg",
      "id_livre": "113",
      "titre": "Une étude en rouge",
      "auteur": "Arthur Conan Doyle",
      "prix": "8",
      "categorie": "30",
      "section": "31"
    },
    {
      "couverture": "http://localhost/drupal/sites/default/files/fables.jpg",
      "id_livre": "119",
      "titre": "Fables",
      "auteur": "Jean de La Fontaine",
      "prix": "0",
      "categorie": "30",
      "section": "31"
    },
    {
      "couverture": "http://localhost/drupal/sites/default/files/couverture-livre_2.png",
      "id_livre": "120",
      "titre": "lire_latin",
      "auteur": "ecri_latin",
      "prix": "33",
      "categorie": "30",
      "section": "31"
    }
  ]
},
{
  "section": "roman drole",
  "id_section": "32",
  "livres": [
    {
      "couverture": "",
      "id_livre": "114",
      "titre": null,
      "auteur": null,
      "prix": "444",
      "categorie": "30",
      "section": "32"
    }
  ]
}

Answer 1

You could try this:

function my_module_home_index(){
  $sections = array();

  $home_livre = db_query("SELECT tax.name as section,field_categorie_tid as tid,field_title_value as titre ,field_prix_value as prix ,t.entity_id FROM {field_data_field_title} as t
    join {field_data_field_prix} as pr on pr.entity_id = t.entity_id
    join {field_data_field_categorie} as cat on cat.entity_id = t.entity_id
    left join {taxonomy_term_data} as tax on tax.tid = cat.field_categorie_tid
    ")->fetchAll();

  foreach($home_livre as $book){
    if (!isset($sections[$book->section])) {
      $sections[$book->section] = array(
        'categorie' => $book->section,
      );
    }

    $sections[$book->section]['livre'][] = array(
      'id_livre' => $book->entity_id,
      'titre' => $book->titre,
      'prix' => $book->prix,
    );
  }

  // The above will set up $sections as an associative array, but you need
  // to return an indexed array, so run it though array_values()
  return array_values($sections);
}

Basically, The first book that comes along with category "A" will create a new child the in $sections array with a key of "A". The book will then be nested in that child. If another book is found with category "A" then instead of creating a new category child, the book is nested inside of the same "A" category.

Note that I've not tested this code live so might need some tweaking