PHP String Functions Explained with Examples

What is String in PHP?

A string is a collection of characters. String is one of the data types supported by PHP.

String variables can contain alphanumeric characters. Strings are created when:

• You declare a variable and assign string characters to it
• You directly use PHP strings with the echo statement.
• PHP string functions are language constructs that help you work with text.
• Learning how strings work in PHP and how to manipulate them will make you a very effective and productive developer.

PHP Create Strings Using Single quotes with Example

Let us now look at the four different ways of creating and manipulating strings in PHP.

Creating PHP strings using single quotes: the simplest way to create a string is to use single quotes.

Let us look at an example that creates a simple string in PHP.

<?php
var_dump('You need to be logged in to view this page');
?>

Output:

string(42) "You need to be logged in to view this page"

If the single quote is part of the string value, it can be escaped using the backslash.

The code below illustrates how to escape a single quote.

<?php
echo 'I \'ll be back after 20 minutes';
?>

Output:

I'll be back after 20 minutes

PHP Create Strings Using Double quotes with Example

Double quotes are used to create relatively complex strings compared to single quotes.

Variable names can be used inside double quotes and their values will be displayed.

Let us look at an example.

<?php
$name = 'Alicia';
echo "$name is friends with kalinda";
?>

HERE,

• The above example creates a simple string with the value of Alicia.
• The variable name is then used in the string created using double quotes, and its value is interpolated at run time.

Output:

Alicia is friends with kalinda

In addition to variable interpolation, the double quote string can also escape more special characters such as “\n for a linefeed, \$ for the dollar sign” etc.

More examples. Let us suppose that we have the following code.

<?php $pwd = "pas$word"; echo $pwd; ?>

Output:

NOTICE : Undefined variable
pas

Executing the above code issues a notice, “Notice: Undefined variable”.

This is because $word is treated as a variable.

If we want the dollar sign to be treated as a literal value, we have to escape it.

<?php
$word = "word";
$pwd = "pas\$word";
echo $pwd; ?>

Output:

pas$word

PHP Heredoc with Example

The heredoc methodology is used to create fairly complex strings compared to double quotes.

Heredoc supports all the features of double quotes and allows creating string values with more than one line without PHP string concatenation.

Using double quotes to create strings that have multiple lines generates an error.

You can also use double quotes inside without escaping them.

The example below illustrates how the heredoc method is used to create string values.

<?php

$baby_name = "Shalon";

echo <<<EOT

When $baby_name was a baby,

She used to look like a "boy".

EOT;

?>

HERE,

<<<EOT is the string delimiter.

EOT is the acronym for end of text.

It should be defined on its own line at the beginning of the string and at the end.

Note: you can use anything you like in place of EOT.

Output:

When Shalon was a baby, She used to look like a "boy".

PHP Nowdoc with Example

The nowdoc string creation method is similar to the heredoc method but works the way single quotes work.

No parsing takes place inside the nowdoc.

Nowdoc is ideal when working with raw data that does not need to be parsed.

The code below shows the nowdoc implementation.

<?php

$baby_name = "Shalon";

$my_variable = <<<'EOT'

When $baby_name was a baby,

She used to look like a "boy".

EOT;

echo $my_variable;

?>

Output:

When $baby_name was a baby, She used to look like a "boy".

PHP String Function Examples

String functions in PHP are used to manipulate string values.

We are now going to look at some of the commonly used string functions in PHP.

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