PHP String Data Type

In PHP, a string data type is a sequence of characters that can contain any character from the ASCII set. Strings are one of the most commonly used data types in PHP for storing and manipulating text data.

PHP provides four different ways to define strings − single quotes, double quotes, heredoc syntax, and nowdoc syntax. Each method has its own characteristics and use cases.

Syntax

// Single quotes
$var = 'Hello World';

// Double quotes  
$var = "Hello World";

// Heredoc
$var = <<< IDENTIFIER
Hello World
IDENTIFIER;

// Nowdoc
$var = <<< 'IDENTIFIER'
Hello World
IDENTIFIER;

Single Quoted Strings

Single quoted strings treat most characters literally. Only the single quote and backslash need to be escaped ?

<?php
$var = 'Hello World.<br> Welcome to Tutorialspoint';
echo $var;
?>

Hello World.<br> Welcome to Tutorialspoint

Double Quoted Strings

Double quoted strings parse escape sequences and allow variable interpolation ?

<?php
$var = "Hello World.<br> Welcome to Tutorialspoint";
echo $var;
?>

Hello World.
 Welcome to Tutorialspoint

Escape Sequences

Double quoted strings recognize the following escape sequences ?

Heredoc Syntax

Heredoc allows multiline strings with variable interpolation. The identifier must start and end on its own line ?

<?php
$name = "Mahesh";
$var = <<< STR
Hello $name
Welcome to Tutorialspoint
STR;
echo $var;
?>

Hello Mahesh
Welcome to Tutorialspoint

Nowdoc Syntax

Nowdoc is similar to heredoc but treats content literally like single quotes. The identifier is enclosed in single quotes ?

<?php
$name = "Mahesh";
$var = <<<'STR'
Hello $name
Welcome to Tutorialspoint
STR;
echo $var;
?>

Hello $name
Welcome to Tutorialspoint

Conclusion

PHP strings offer flexible options for text handling. Use single quotes for literal strings, double quotes when you need escape sequences or variable interpolation, and heredoc/nowdoc for multiline content.