PHP Numbers

PHP has three primary types of numbers: Integers, Floats, and Number Strings. Additionally, there are special types like Infinity and NaN.

PHP Numbers

Main Numeric Types in PHP:

1. Integer: Whole numbers without decimal points.
2. Float: Numbers with decimal points or in exponential form.
3. Number Strings: Strings that represent numeric values.

Special Numeric Types in PHP:

• Infinity: Represents values larger than PHP_FLOAT_MAX.
• NaN (Not a Number): Used for invalid mathematical operations.

Creating Variables

To create numeric variables, simply assign values to them:

$age = 25;
$price = 399.99;
$year = "2025";

$age = 25;

$price = 399.99;

$year = "2025";

Checking Variable Types

Use var_dump() to check the type of any variable:

var_dump($age);
var_dump($price);
var_dump($year);

var_dump($age);

var_dump($price);

var_dump($year);

PHP Integers

An integer is a whole number without any decimal part. Here are a few examples: 10, -15, 2000. Integers in PHP can be between -2147483648 and 2147483647 on 32-bit systems, and much larger on 64-bit systems.

Rules for Integers:

• Must have at least one digit
• No decimal point allowed
• Can be positive or negative

Constants for Integers:

• PHP_INT_MAX: Maximum integer
• PHP_INT_MIN: Minimum integer
• PHP_INT_SIZE: Size of an integer in bytes

Functions to Check Integer Type:

• is_int()
• is_integer() (alias of is_int())
• is_long() (alias of is_int())

Example: Checking Integer Type

$engine_capacity = 1200;
var_dump(is_int($engine_capacity));

$engine_capacity = 1200.5;
var_dump(is_int($engine_capacity));

$engine_capacity = 1200;

var_dump(is_int($engine_capacity));

​

$engine_capacity = 1200.5;

var_dump(is_int($engine_capacity));

PHP Floats

A float is a number with a decimal point or in exponential form. Examples: 3.14, 0.001, 2.5E+3.

Constants for Floats:

• PHP_FLOAT_MAX: Largest floating point number
• PHP_FLOAT_MIN: Smallest positive floating point number
• PHP_FLOAT_DIG: Number of decimal digits without precision loss
• PHP_FLOAT_EPSILON: Smallest positive number x so that x + 1.0 != 1.0

Functions to Check Float Type:

• is_float()
• is_double() (alias of is_float())

Example: Checking Float Type

$mileage = 15.75;
var_dump(is_float($mileage));

$mileage = 15.75;

var_dump(is_float($mileage));

PHP Infinity

Values larger than PHP_FLOAT_MAX are considered infinite.

Functions to Check Finite/Infinite Values:

• is_finite()
• is_infinite()

Example: Checking Finite/Infinite Value

$speed = 1.8e309;
var_dump($speed);

$speed = 1.8e309;

var_dump($speed);

PHP NaN

NaN stands for “Not a Number”. It results from invalid mathematical operations.

Function to Check NaN:

• is_nan()

Example: NaN Value

$result = acos(8);
var_dump($result);

$result = acos(8);

var_dump($result);

PHP Numerical Strings

To determine if a variable is numeric, use the is_numeric() function. It returns true if the variable is a number or a numeric string, and false otherwise.

Example: Checking Numeric Strings

$model_number = 7500;
var_dump(is_numeric($model_number));

$model_number = "7500";
var_dump(is_numeric($model_number));

$model_number = "75.00" + 100;
var_dump(is_numeric($model_number));

$model_number = "Speedster";
var_dump(is_numeric($model_number));

$model_number = 7500;

var_dump(is_numeric($model_number));

​

$model_number = "7500";

var_dump(is_numeric($model_number));

​

$model_number = "75.00" + 100;

var_dump(is_numeric($model_number));

​

$model_number = "Speedster";

var_dump(is_numeric($model_number));

Casting Strings and Floats to Integers

Sometimes you need to convert a value to an integer. Use (int), (integer), or intval() for this purpose.

Example: Casting to Integer

// Cast float to int
$engine_capacity = 2345.678;
$int_cast = (int)$engine_capacity;
echo $int_cast;

echo "<br>";

// Cast string to int
$engine_capacity = "2345.678";
$int_cast = (int)$engine_capacity;
echo $int_cast;

// Cast float to int

$engine_capacity = 2345.678;

$int_cast = (int)$engine_capacity;

echo $int_cast;

​

echo "<br>";

​

// Cast string to int

$engine_capacity = "2345.678";

$int_cast = (int)$engine_capacity;

echo $int_cast;