A multidimensional array is an array that contains one or more arrays as its elements. It is useful for storing structured data such as student records, employee details, product lists, and marksheets.
A normal array stores a list of values. A multidimensional array can store multiple arrays inside a parent array.
<?php
$students = [
["Rahul", 20, "PHP"],
["Amit", 21, "Java"],
["Priya", 19, "Python"]
];
print_r($students);
?>Array
(
[0] => Array
(
[0] => Rahul
[1] => 20
[2] => PHP
)
[1] => Array
(
[0] => Amit
[1] => 21
[2] => Java
)
[2] => Array
(
[0] => Priya
[1] => 19
[2] => Python
)
)Each inner array represents one student and contains that student's name, age, and course.
A two-dimensional array can be visualized as rows and columns, similar to a table.
<?php
$marks = [
[80, 85, 90],
[75, 88, 92],
[90, 95, 89]
];
print_r($marks);
?>| Student | Subject 1 | Subject 2 | Subject 3 |
|---|---|---|---|
| Student 1 | 80 | 85 | 90 |
| Student 2 | 75 | 88 | 92 |
| Student 3 | 90 | 95 | 89 |
Each outer index identifies a row, and each inner index identifies a value within that row.
Use multiple square-bracket indexes to access values inside nested indexed arrays.
<?php
$students = [
["Rahul", 20, "PHP"],
["Amit", 21, "Java"],
["Priya", 19, "Python"]
];
echo $students[0][0];
echo "<br>";
echo $students[0][2];
echo "<br>";
echo $students[1][0];
echo "<br>";
echo $students[2][2];
?>Rahul
PHP
Amit
Python
For example, $students[1][0] accesses
the first value in the second inner array.
You can use named keys inside each nested array to make records easier to understand.
<?php
$students = [
[
"name" => "Rahul",
"age" => 20,
"course" => "PHP"
],
[
"name" => "Amit",
"age" => 21,
"course" => "Java"
],
[
"name" => "Priya",
"age" => 19,
"course" => "Python"
]
];
echo $students[0]["name"];
echo "<br>";
echo $students[1]["course"];
echo "<br>";
echo $students[2]["age"];
?>Rahul
Java
19This structure is useful when every record has properties such as name, age, course, or email.
You can update or add values inside an inner array by using its keys.
<?php
$students = [
[
"name" => "Rahul",
"marks" => 80
],
[
"name" => "Amit",
"marks" => 75
]
];
// Update marks
$students[0]["marks"] = 90;
// Add a new field
$students[0]["course"] = "PHP";
// Add another student
$students[] = [
"name" => "Priya",
"marks" => 95
];
// Remove a field
unset($students[1]["marks"]);
print_r($students);
?>The first student's marks are updated, a course field is added, a new student is appended, and the marks field is removed from the second student.
Important: After using
unset(), the remaining keys are not
automatically renumbered.
A foreach loop inside another foreach loop can display values from nested arrays.
<?php
$students = [
["Rahul", 20, "PHP"],
["Amit", 21, "Java"],
["Priya", 19, "Python"]
];
foreach ($students as $student) {
foreach ($student as $value) {
echo $value . " ";
}
echo "<br>";
}
?>Rahul 20 PHP
Amit 21 Java
Priya 19 PythonThe outer loop accesses each student record, and the inner loop displays the values within that record.
Display keys and values:
<?php
$students = [
[
"name" => "Rahul",
"course" => "PHP"
],
[
"name" => "Amit",
"course" => "Java"
]
];
foreach ($students as $index => $student) {
echo "Student " . ($index + 1) . "<br>";
foreach ($student as $key => $value) {
echo $key . ": " . $value . "<br>";
}
echo "<hr>";
}
?>Multidimensional arrays can be used to generate HTML tables dynamically.
<?php
$students = [
["name" => "Rahul", "course" => "PHP", "marks" => 85],
["name" => "Amit", "course" => "Java", "marks" => 90],
["name" => "Priya", "course" => "Python", "marks" => 95]
];
?>
<table border="1" cellpadding="8">
<tr>
<th>Name</th>
<th>Course</th>
<th>Marks</th>
</tr>
<?php foreach ($students as $student): ?>
<tr>
<td>
<?= htmlspecialchars($student["name"], ENT_QUOTES, "UTF-8") ?>
</td>
<td>
<?= htmlspecialchars($student["course"], ENT_QUOTES, "UTF-8") ?>
</td>
<td>
<?= htmlspecialchars((string) $student["marks"], ENT_QUOTES, "UTF-8") ?>
</td>
</tr>
<?php endforeach; ?>
</table>| Name | Course | Marks |
|---|---|---|
| Rahul | PHP | 85 |
| Amit | Java | 90 |
| Priya | Python | 95 |
htmlspecialchars() helps prevent HTML
markup in text values from being interpreted as HTML.
It is a useful habit when displaying user-provided data.
We can calculate each student's total and average using values stored in a multidimensional array.
<?php
$students = [
[
"name" => "Rahul",
"marks" => [80, 85, 90]
],
[
"name" => "Amit",
"marks" => [75, 88, 92]
],
[
"name" => "Priya",
"marks" => [90, 95, 89]
]
];
foreach ($students as $student) {
$total = array_sum($student["marks"]);
$subjects = count($student["marks"]);
$average = $subjects > 0 ? $total / $subjects : 0;
echo "Name: " . $student["name"] . "<br>";
echo "Total: " . $total . "<br>";
echo "Average: " . number_format($average, 2) . "<br>";
echo "<hr>";
}
?>Name: Rahul
Total: 255
Average: 85.00
Name: Amit
Total: 255
Average: 85.00
Name: Priya
Total: 274
Average: 91.33
array_sum() adds the marks, while
count() determines the number of subjects.
number_format() displays the average
with two decimal places.
An array can contain another array that contains additional arrays. This structure is called a multidimensional array with three levels when three indexes are used to access a value.
<?php
$school = [
"Class 10" => [
"Section A" => [
"Rahul",
"Amit"
],
"Section B" => [
"Priya",
"Neha"
]
],
"Class 12" => [
"Section A" => [
"Ravi",
"Pooja"
]
]
];
echo $school["Class 10"]["Section A"][0];
echo "<br>";
echo $school["Class 10"]["Section B"][1];
echo "<br>";
echo $school["Class 12"]["Section A"][0];
?>Rahul
Neha
RaviThe first key selects a class, the second key selects a section, and the numeric index selects a student.
1. What is a multidimensional array?
2. How do you access the first element of the second inner array in $data?
3. Which function calculates the sum of numeric values in an array?