Strings3:43 with Alena Holligan
A string is a series of characters, typically specified within quotations. Explore the differences between single and double quoted strings and using other variables within a string.
Learn more about Strings
Single Quoted Strings are the simplest way to specify a string. Enclose the string in single quotes (the character ').
To specify a literal single quote, escape it with a backslash (\'). To specify a literal backslash, double it (\\). All other instances of backslash will be treated as a literal backslash: this means that the other escape sequences you might be used to, such as \r or \n, will be output literally as specified rather than having any special meaning.
Note: variables and escape sequences for special characters will not be expanded when they occur in single quoted strings.
Double Quoted Strings are enclosed in double-quotes ("), PHP will interpret more escape sequences for special characters. As in single quoted strings, escaping any other character will result in the backslash being printed too.
The most important feature of double-quoted strings is the fact that variable names will be expanded.
Although quotes are the primary way to specify a string, there is another option: the heredoc syntax (<<<). After this operator, an identifier is provided, then a newline. The string itself follows, and then the same identifier again to close the quotation.
The closing identifier must begin in the first column of the line. Also, the identifier must follow the same naming rules as any other label in PHP: it must contain only alphanumeric characters and underscores, and must start with a non-digit character or underscore.
Heredoc syntax allows people to easily write large amounts of text from within PHP, but without the need to constantly escape things. Put simply, it allows you to define your own string limiter so that you can make it something other than a double or single quote. So, for example, we could use the string "EOT" (end of text) for our delimiter, meaning that we can use double quotes and single quotes freely within the body of the text - the string only ends when we type EOT.
$name = 'Alena'; $myString = <<<EOT Example of string spanning multiple lines using spaces and including a $name variable using heredoc syntax. EOT;
Example of string spanning multiple lines using spaces and including a Alena variable using heredoc syntax.
Nowdocs are to single-quoted strings what heredocs are to double-quoted strings. A nowdoc is specified similarly to a heredoc, but no parsing is done inside a nowdoc. The construct is ideal for embedding PHP code or other large blocks of text without the need for escaping.
A nowdoc is identified with the same <<< sequence used for heredocs, but the identifier which follows is enclosed in single quotes, e.g. <<<'EOT'. All the rules for heredoc identifiers also apply to nowdoc identifiers, especially those regarding the appearance of the closing identifier.
$name = 'Alena'; $str = <<<'EOT' Example of string spanning multiple lines using spaces and including a $name variable using nowdoc syntax. EOT;
Example of string spanning multiple lines using spaces and including a $name variable using nowdoc syntax.
You need to sign up for Treehouse in order to download course files.Sign up