Strings in PHP is a combination or sequence of characters, numbers and special symbols. In PHP, strings can be represented in

  1. Double quotes
  2. Single quotes
  3. Heredoc
  4. Newdoc

String in Double quote

<?php
 $name = "PHP";
 echo  $name;
?>

String in Single quote

<?php
 $name = 'PHP string';
 echo  $name;
?>

Multiline string

Both single quote or double quotes can be used to create multiline string.

<?php
 $text = 'PHP 
          string
          Tutorial...';
 echo  $text;
?>

Heredoc

Heredoc allows to create a string without single or double quotes, and also allows to use your own string identifier.

Syntax

<?php
  $text = <<<IDENTIFIER

  IDENTIFIER;
?>

Heredoc uses three less than symbol and IDENTIFIER and a newline and Ends with IDENTIFIER and semicolon. Start identifier and End identifier name must be same.

Space is allowed between <<< IDENTIFIER.

Example

<?php
  $age = 20;
  $text = <<<MYTEXT
   Hello this is Heredoc example,
   You can use 'single quote' and  "Double quote" 
   in Heredoc.
   Variables are also allowed $age value is printed with the string output.
   You can add as many line as you can.
  MYTEXT;
?>

<<<identifier, Here you can create your own identifier like in above example <<<MYTEXT, and identifier should ends with same name MYTEXT;

Heredoc has following advantages

  1. Single quotes and double quotes can be used inside Heredoc.
  2. Multiline strings can be used.
  3. Variable can also be used with heredoc string. and it outputs variable value in string.

Nowdoc

Nowdoc is similar to Heredoc with a small difference, ‘IDENTIFIER’ must be inside single quote and not able to print or outputs variables value inside string.

Syntax

<?php
  $text = <<<'IDENTIFIER'

  IDENTIFIER;
?>