PHP Numbers

In PHP, numbers represent numeric values and can be broadly categorized into two main types:

There are three main numeric types in PHP:

• Integer
Represent whole numbers without decimal points.
Range depends on your system's architecture: 32-bit system: -2,147,483,648 to 2,147,483,647
64-bit system: -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

• Float

Represent numbers with decimal points or in scientific notation (e.g., 2.5E+3).
Have higher precision than integers but are less precise than arbitrary-precision libraries.
• Number Strings

In addition, PHP has two more data types used for numbers:

• Infinity

• NaN

Example

 $a = 5;
 $b = 5.34;
 $c = "25";

To verify the type of any object in PHP, use the var_dump() function:

Example

<!DOCTYPE html>
<html>
<body>

<?php
$a = 5;
$b = 5.34;
$c = "25";

var_dump($a);
echo "<br>";
var_dump($b);
echo "<br>";
var_dump($c);
?> 

<p>Line breaks were added for better readability.</p>

</body>
</html>

Output

int(5)
float(5.34)
string(2) "25"
Line breaks were added for better readability.

PHP Integers

2, 256, -256, 10358, -179567 are all integers.

An integer is a number without any decimal part.

An integer data type is a non-decimal number between -2147483648 and 2147483647 in 32 bit systems, and between -9223372036854775808 and 9223372036854775807 in 64 bit systems. A value greater (or lower) than this, will be stored as float, because it exceeds the limit of an integer.

Here are some rules for integers:

1 • An integer must have at least one digit

2 • An integer must NOT have a decimal point

3 • An integer can be either positive or negative

4 • Integers can be specified in three formats: decimal (10-based), hexadecimal (16-based - prefixed with 0x) or octal (8-based - prefixed with 0)

PHP has the following predefined constants for integers:

• PHP_INT_MAX - The largest integer supported

• PHP_INT_MIN - The smallest integer supported

• PHP_INT_SIZE - The size of an integer in bytes

PHP has the following functions to check if the type of a variable is integer:

• is_int()

• is_integer() - alias ofis_int()

• is_long() - alias of is_int()

Example

<!DOCTYPE html>
<html>
<body>

bool(true)
<br>bool(false)
  

</body>
</html>

Output

bool(true)
bool(false)

PHP Floats

A float is a number with a decimal point or a number in exponential form.

2.0, 256.4, 10.358, 7.64E+5, 5.56E-5 are all floats.

The float data type can commonly store a value up to 1.7976931348623E+308 (platform dependent), and have a maximum precision of 14 digits.

PHP has the following predefined constants for floats (from PHP 7.2):

• PHP_FLOAT_MAX - The largest representable floating point number

• PHP_FLOAT_MIN - The smallest representable positive floating point number

• PHP_FLOAT_DIG - The number of decimal digits that can be rounded into a float and back without precision loss

• PHP_FLOAT_EPSILON - The smallest representable positive number x, so that x + 1.0 != 1.0

PHP has the following functions to check if the type of a variable is float:

• is_float()

• is_double() - alias of is_float()

Example

<!DOCTYPE html>
<html>
<body>

<?php
// Check if the type of a variable is float 
$x = 10.365;
var_dump(is_float($x));
?>  

</body>
</html>

Output

bool(true)

PHP Infinity

A numeric value that is larger than PHP_FLOAT_MAX is considered infinite.

PHP has the following functions to check if a numeric value is finite or infinite:

• is_finite()
• is_infinite()

Example

<!DOCTYPE html>
<html>
<body>

<?php
// Check if a numeric value is finite or infinite 
$x = 1.9e411;
var_dump($x);
?>  

</body>
</html>

Output

float(INF)

PHP NaN

NaN stands for Not a Number.
NaN is used for impossible mathematical operations.

PHP has the following functions to check if a value is not a number:

• is_nan()

However, the PHP var_dump() function returns the data type and value:

Example

<!DOCTYPE html>
<html>
<body>

<?php
// Invalid calculation will return a NaN value
$x = acos(8);
var_dump($x);
?>  

</body>
</html>

Output

float(NAN)

PHP Numerical Strings

The PHP is_numeric() function can be used to find whether a variable is numeric. The function returns true if the variable is a number or a numeric string, false otherwise.

Example

<!DOCTYPE html>
<html>
<body>

<?php
// Check if the variable is numeric   
$x = 5985;
var_dump(is_numeric($x));

echo "<br>";

$x = "5985";
var_dump(is_numeric($x));

echo "  

</body>
</html>

Output

bool(true)
bool(true)
bool(true)
bool(false)