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PHP Type Casting

Type casting means converting one data type into another.

PHP automatically converts data types when needed, but you can also manually convert them.

Why Type Casting?

Type casting is useful when:

✅ Receiving user input

✅ Working with databases

✅ Processing APIs

✅ Handling configuration files

✅ PocketMine plugin development

Automatic Type Conversion

PHP automatically converts types.

Example:

$a = "10";
$b = 5;

echo $a + $b;

Output:

15

PHP automatically converts "10" into an integer.

Manual Type Casting

PHP supports the following casts:

(int)
(float)
(string)
(bool)
(array)
(object)
unset()

Integer Casting

String → Integer​

$number = (int) "50";

echo $number;

Output:

50

Float → Integer​

$number = (int) 99.99;

echo $number;

Output:

99

⚠ Decimal part is removed.

Boolean → Integer​

echo (int) true;

Output:

1
echo (int) false;

Output:

0

Float Casting

$number = (float) "50";

var_dump($number);

Output:

float(50)

Example:

$health = 20;

$speed = (float) $health;

String Casting

Integer → String​

$name = (string) 50;

var_dump($name);

Output:

string(2) "50"

Boolean → String​

echo (string) true;

Output:

1

Array → String​

echo (string) [];

Produces:

Warning

Boolean Casting

Integer → Boolean​

(bool) 1

Output:

true
(bool) 0

Output:

false

String → Boolean​

(bool) "Hello"

Output:

true
(bool) ""

Output:

false

Array Casting

String → Array​

$data = (array) "Aayan";

print_r($data);

Output:

Array
(
    [0] => Aayan
)

Integer → Array​

$data = (array) 10;

Output:

Array
(
    [0] => 10
)

Object Casting

Array → Object​

$user = [
    "name" => "Aayan",
    "age" => 18
];

$obj = (object) $user;

echo $obj->name;

Output:

Aayan

Null Casting

(int) null

Output:

0
(string) null

Output:

""
(bool) null

Output:

false

Type Juggling

PHP automatically changes data types.

Example:

echo "10" + "20";

Output:

30

Example:

echo "100 players";

PHP keeps it as a string.

Strict Types

Always use:

declare(strict_types=1);

Without strict types:

function add(
    int $a
) {

}

add("10");

Works.

With strict types:

TypeError

Useful Functions

intval()​

intval("50");

floatval()​

floatval("5.5");

strval()​

strval(100);

boolval()​

boolval(1);

settype()​

$value = "50";

settype($value, "integer");

Type Checking Functions

is_int()
is_float()
is_bool()
is_string()
is_array()
is_object()

Real World Examples

Form Input​

$age =
(int) $_POST["age"];

Config Values​

$port =
(int) $config["port"];

PocketMine​

$health =
(int) $player->getHealth();

Economy Plugin​

$money =
(float) $data["money"];

Memory Representation

String
 ↓
"50"

(int)

 ↓

50

Common Mistakes

❌

$number = "abc";

echo (int) $number;

Output:

0

❌

(bool) "false"

Output:

true

Many beginners think this becomes false.

Any non-empty string becomes:

true

Best Practices

✅ Validate before casting.

if (is_numeric($value)) {

}

✅ Use strict types.

✅ Use explicit casting.

Exercises

Exercise 1​

Convert:

"100"

to integer.

Exercise 2​

Convert:

10

to string.

Exercise 3​

Convert:

[
    "name" => "Aayan"
]

to object.

Challenge

Create:

$name = "50";
$health = "20";
$money = "1000.50";

Convert them into proper types.

Quiz

What is:​

(int) "50"
Answer

50

What is:​

(bool) ""
Answer

false

What is:​

(bool) "false"
Answer

true

References

PHP Type Casting:

https://www.php.net/manual/en/language.types.type-juggling.php

PHP settype():

https://www.php.net/manual/en/function.settype.php

Next Chapter

➡ PHP Operators