Variables In PHP

This post describes PHP Variables in a way that is in compliance with educational standards.

A variable can be thought of as a “container” for storing information.

PHP Variables

PHP Variables can be named in two ways: short and descriptive (example a and b), and long and descriptive (example: name, greeting, area_surface).

A variable in PHP is created by starting with a $ sign, followed by the variable’s name.

For example:


<?php $name = "Bill Gates!"; $a = 3; $b = 6.2; ?>


<?php $string = "Bill Gates is the co-founder of Microsoft"; $l = 18.2; $m = 7; ?>

As a result of executing the above statements, the variable will be:

$name holds the value of Bill Gates!, $a holds the value of 3, And variable $b holds the value of 6.2.

Remember: Put quotes around text values when assigning them to variables.

IMPORTANT: PHP does not have a command for declaring variables. As soon as you assign a value to it, it is created.

A variable is a container for storing data.

PHP Variable Output

To display data on a screen, PHP echo is often used.

Below is an example showing how to display text and a variable:


<?php $link = ""; echo "I love $link!"; ?>


<?php $name = "Bill Gates"; echo "This is $name, from microsoft!"; ?>

Similar to the above example, this example will produce the following output:


<?php $link = ""; echo "I love" . $link . "!"; ?>


<?php $name = "Bill Gates"; echo "This is " . $name . ", from microsoft!"; ?>

Here is a simple example that sums two variables:


<?php $a = 3; $b = 8; echo $a + $b; ?>

The example above demonstrates that PHP did not require us to specify the variable’s data type.

Depending on the variable’s value, PHP automatically assigns a data type.

It is possible to add a string to an integer without causing an error because the data types are not strictly defined.

Type declarations were added to PHP 7. If a type mismatch occurs when declaring a function, the strict requirement will throw a “Fatal Error”.

Remember: In the next chapter, you’ll learn more about how to output data to the screen using the echo statement.

PHP Variables Key Points

When declaring a variable in PHP, remember the following key points:

  1. Variable names begin with the $ sign, followed by the variable name.
  2. There must be a letter or underscore at the beginning of a variable name.
  3. Variable names cannot begin with a number.
  4. There can be only alphanumeric characters and underscores in variable names (A-z, 0-9, and _).
  5. It is recommended to use descriptive and meaningful names for variables to improve code readability and maintainability.
  6. The names of variables are case-sensitive ($name and $NAME are two different variables).
  7. Variables are assigned values using the “=” operator.
  8. The value of a variable can be changed throughout the program by reassigning it a new value.
  9. PHP is a dynamically-typed language, which means that the data type of a PHP variable can change automatically based on the value it is assigned. This is known as type juggling and can sometimes lead to unexpected results if not handled properly.
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