PHP Numbers

PHP Numbers

One thing to notice about PHP is that it provides automatic data type conversion.

So, if you assign an integer value to a variable, the type of that variable will automatically be an integer. Then, if you assign a string to the same variable, the type will change to a string.

This automatic conversion can sometimes break your code.

An integer is a number without any decimal part.

2, 256, -256, 10358, -179567 are all integers. While 7.56, 10.0, 150.67 are floats.

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

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

Example:

<?php
$x = 5985;
var_dump(is_int($x));

$x = 59.85;
var_dump(is_int($x));
?>

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

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

Example

Check if the type of a variable is float:

<?php
$x = 10.365;
var_dump(is_float($x));
?>

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()

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

Example

Check if a numeric value is finite or infinite:

<?php
$x = 1.9e411;
var_dump($x);
?>

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

Check if the variable is numeric:

<?php
$x = 5985;
var_dump(is_numeric($x));

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

$x = "59.85" + 100;
var_dump(is_numeric($x));

$x = "Hello";
var_dump(is_numeric($x));
?>

PHP Casting Strings and Floats to Integers

Sometimes you need to cast a numerical value into another data type.

The (int), (integer), or intval() function are often used to convert a value to an integer.

Example

Cast float and string to integer:

<?php
// Cast float to int$x = 23465.768;
$int_cast = (int)$x;
echo $int_cast;

echo "<br>";

// Cast string to int$x = "23465.768";
$int_cast = (int)$x;
echo $int_cast;
?>