Multidimensional array in PHP

Current PHP usage

A multidimensional array contains arrays as values. Access deeper values by chaining keys or indexes, and use nested foreach loops when you need to traverse every level.

$students = [
    ['name' => 'Ana', 'mark' => 81],
    ['name' => 'Ben', 'mark' => 76]
];
echo $students[0]['name'];

For record-like arrays, descriptive string keys make nested data easier to read and maintain.

A multidimensional array stores arrays inside another array. The example below creates a two-dimensional structure.

$a=array(array("path"=>"php_tutorial","section"=>"php"),
array("path"=>"sql_tutorial","section"=>"sql"),
array("path"=>"javascript_tutorial","section"=>"js"),
array("path"=>"html_tutorial","section"=>"html"),
);

Now to display the elements of this array we can use like this.

$max=sizeof($a);
for($i=0; $i<$max; $i++) { 

foreach ($a[$i] as $key => $val) { 
echo "$key -> $val <br>"; 
} // inner array while loop

} // outer array for loop

The output is here

path -> php_tutorial 
section -> php 
path -> sql_tutorial 
section -> sql 
path -> javascript_tutorial 
section -> js 
path -> html_tutorial 
section -> html

To display individual element

echo $a[2]['path'];

Output is here

javascript_tutorial

Adding elements to Multidimensional array

$a=array(array("product"=>"apple","quantity"=>2),
array("product"=>"Orange","quantity"=>4),
array("product"=>"Banana","quantity"=>5),
array("product"=>"Mango","quantity"=>7),
); 

$b=array("product"=>"Lemon","quantity"=>9);
array_push($a,$b);
//$a[]=$b;
$max=sizeof($a);
for($i=0; $i<$max; $i++) { 

foreach ($a[$i] as $key => $val) { 
echo "$key -> $val "; 
} // inner array while loop
echo "<br>";
} // outer array for loop

Adding elements to multidimensional array from database table.

We will try to add elements to a multidimensional array by taking records from a database table. Here we are looping through all the records to display records and at the same time adding the record to array.

$data=array("id"=>$row['id'],"name"=>$row['name']);

Note that each student record is an array and it is added to our main array. There are two columns we used and you can extend it to include more columns.
Here is the full code

<?Php
require "config.php";// database connection
$sql="SELECT *  FROM student"; 
$my_array=array();
foreach ($dbo->query($sql) as $row) {
//echo "$row[id] , $row[name],$row[class],$row[mark]<br>";
$data=array("id"=>$row['id'],"name"=>$row['name']);
$my_array[]=$data;
}
echo $my_array[5]['name']; // displaying single record
echo "<hr>";
$max=sizeof($my_array);
for($i=0; $i<$max; $i++) { 
// displaying all the elements
foreach ($my_array[$i] as $key => $val) { 
echo "$key -> $val <br>"; 
} // inner array while loop

} // outer array for loop

?>

Displaying single element ( record )

echo $my_array[5]['name']; // displaying single record

You can read more on how to connect to database

ARRAY REFERENCE Joining Two Arrays by array_merge

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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