PHP String Data Type

Definition and Usage

In PHP, a string data type is a non-numeric sequence of charaters.Any character in the ASCII set can be a part of a string. PHP doesn't support UNICODE.

In PHP, literal representation of string can be done with single quotes, double quotes, with heredoc syntax and nowdoc syntax.

Syntax

//Literal assignment of string value to variable
$var='Hello World'; //Single quotes
$var3="Hello World"; //Double quotes

To embed single quote character inside single quoted string prefix it with '\'. Similarly to embed backslash in single quoted string prefix it with additional backslash. Other escape sequence characters such as \n etc. do not carry any special representation.

Double quoted string treats following escape sequences with their special meaning as follows:

The Heredoc string starts with <<< symbol followed by any identifier of user's choice. From next line, any multiline sequence of characters that may be having any of the above escape sequences. Last line should have same heredoc identifier ending with semicolon.

//Heredoc assignment of string value to variable
public $var = <<< XYZ
Hello World
Welcome to Tutorialspoint
XYZ;

Nowdoc strings are similar to heredoc strings. Difference is that identifier must be enclosed in single quotes and escape sequences inside nowdoc string are not parsed and appear as it is.

//Nowdoc assignment of string value to variable
public $var = <<< 'XYZ'
Hello World
Welcome to Tutorialspoint
XYZ;

PHP Version

Use of separation symbol "_" is avilable since PHP 7.40

Following example shows single quoted string. The escape sequence \n is not parsed and appears as it is

Example

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

Output

This will produce following result −

Hello World.\n Welcome to Tutorialspoint

This Example double quoted string. The escape sequence \n is parsed and text appears in two lines

Example

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

Output

This will produce following result −

Hello World.
Welcome to Tutorialspoint

This example shows how to use Heredoc and Nowdoc syntax for string representation

Example

<?php
//Heredoc
$var = <<< STR
Hello World
Welcome to Tutorialspoint
STR;
echo $var . "\n";
//Nowdoc
$var = <<< 'STR'
Hello World
Welcome to Tutorialspoint
STR;
echo $var;
?>

Output

This will produce following result −

Hello World
Welcome to Tutorialspoint
Hello World
Welcome to Tutorialspoint

This Example shows values of a variable is substiuted in heredoc string. Nowdoc string doesn't make substitution

Example

<?php
$name = "Mahesh";
$var = <<< STR
Hello $name
Welcome to Tutorialspoint
STR;
echo $var . "\n";
//Nowdoc
$var = <<<'STR'
Hello $name
Welcome to Tutorialspoint
STR;
echo $var;
?>

Output

This will produce following result −

Hello Mahesh
Welcome to Tutorialspoint
Hello $name
Welcome to Tutorialspoint