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C # tutorial
Variables are "containers" for storing information
In PHP, a variable starts with the $ sign, followed by the name of the variable:
<?php
$txt = "Hello world!";
$x = 5;
$y = 10.5;
?>
After the execution of the statements above, the variable
$txt will hold the value
Hello world!, the variable
$x will hold the value
5,
and the variable $y will hold the value
10.5.
Think of variables as containers for storing data.
A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume).
Rules for PHP variables:
$ sign, followed by the name of the variable$age and
$AGE are two different variables)Remember that PHP variable names are case-sensitive!
The PHP echo statement is often used to output data to the screen.
The following example will show how to output text and a variable:
<?php
$txt = "W3C";
echo "I love $txt!";
?>
The following example will produce the same output as the example above:
<?php
$txt = "W3C";
echo "I love " . $txt . "!";
?>
The following example will output the sum of two variables:
<?php
$x = 5;
$y = 4;
echo $x + $y;
?>
echo statement and how
to output data to the screen in the next chapter.
In the example above, notice that we did not have to tell PHP which data type the variable is.
PHP automatically associates a data type to the variable, depending on its value. Since the data types are not set in a strict sense, you can do things like adding a string to an integer without causing an error.
In PHP 7, type declarations were added. This gives an option to specify the data type expected when declaring a function, and by enabling the strict requirement, it will throw a "Fatal Error" on a type mismatch.
You will learn more about strict and
non-strict requirements, and
data type declarations in the PHP Functions chapter.