PHP Lessons - Lesson 4 - PHP Numeric Variables

In the previous lesson, we explored string variables. Now, let’s take a look at numeric variables. The simplest type of number is the integer.

Integers in PHP

Integers are whole numbers in the range from –2,147,483,648 to 2,147,483,647. This range is determined by the 32-bit memory space used to store integers.

Just like other variables in PHP, integers are assigned with a simple assignment statement:

<?php
$x = 5;
$y = -8;
?>

Apart from decimal numbers, PHP also supports other number systems like octal and hexadecimal:

<?php
$i = 456;   // decimal
$i = -895;  // negative decimal
$i = 0121;  // octal (equivalent to 81 in decimal)
$i = 0x1B;  // hexadecimal (equivalent to 27 in decimal)
?>

In addition to integers, PHP supports floating-point numbers.

Floating-Point Numbers (float) in PHP

Floating-point numbers are decimal numbers and can be defined like this:

<?php
$pi = 3.14;
?>

Note that the decimal point is a period (.), not a comma. PHP also supports scientific notation:

<?php
$b = 3.2e5;  // equivalent to 320000
$c = 9E-11;  // equivalent to 0.00000000009
?>

Floating-point numbers (also called numbers with a floating point) use 64 bits of memory—twice as much as integers.

Often, float values are the result of division:

<?php
$a = 1/3;
print $a;
?>

The result will be:

0.333333333333

But sometimes the result might not be what you expect at first glance:

<?php
$a = 1/3;
$a = $a * 3;
print $a;
?>

Here, PHP will output exactly:

1

If you did this on a calculator, you’d likely get 0.9999999 due to rounding limitations. PHP, however, retains the mathematical precision of operations whenever possible, ensuring accurate results without data loss.