PHP Lessons - Lesson 3 - PHP String Variables

In the previous lesson, we discussed that PHP supports variables. In this lesson, we'll take a look at one type of variable — string variables.

String variables in PHP are used to store values that consist of characters. A PHP string can be saved in a variable. Below is a PHP script that assigns the text "Hello, World!" to the string variable $txt:

<?php
$txt = "Hello, World!";
echo $txt;
?>

The result of the code above:

Hello World!

Now let's try a few different functions and operators to manipulate strings.

String Concatenation Operator in PHP

PHP has only one string operator: the concatenation operator, which is a period .. This operator is used to combine two string values. To concatenate two string variables, use the concatenation operator like this:

<?php
$txt1 = "Hello, World!";
$txt2 = "How are you?";
echo $txt1 . " " . $txt2;
?>

The result of the code above:

Hello, World! How are you?

As you can see, we used the concatenation operator twice. That's because we inserted a third string — a space — between the two messages to separate them.

You may also have noticed that the output is printed on one line. To print it on a new line, you can use HTML tags like <br /> or <p></p>:

<?php
$txt1 = "Hello, World!";
$txt2 = "How are you?";
print $txt1 . "<br />" . $txt2;
?>

Result:

Hello, World!

How are you?

Using the <p> tag:

<?php
$txt1 = "Hello, World!";
$txt2 = "How are you?";
print "<p>" . $txt1 . "</p><p>" . $txt2 . "</p>";
?>

Same visual result, but different HTML output:

<p>Hello, World!</p>

<p>How are you?</p>

PHP strlen() Function

The strlen() function returns the length of a string. Let's get the length of a string:

<?php
echo strlen("Hello, World!");
?>

Result:

12

Knowing the length of a string is useful in loops or other logic where it's important to detect the end of a string.

PHP strpos() Function

The strpos() function is used to find the position of a substring in a string. If a match is found, it returns the position of the first match; if not, it returns FALSE. Let's try finding the word "World" in our string:

<?php
echo strpos("Hello, World!", "World");
?>

Result:

7

The position is 7 because string positions start at 0, not 1.