Tinsology

If you are at all familiar with PHP you are probably aware that you can put variables inside double quotes. For example:

$x = 5;
echo "x is equal to $x";

The above code will output “x is equal to 5″. This method works fine with simple variables, but will fail with references to member variables of objects or arrays:

//will not work
echo "x is equal to $myObject->x";

//also won't work
echo "x is equal to $myArra['x']";

To avoid this problem, PHP allows you to use curly braces to seperate variables that need to be parsed:

//will work
echo "x is equal to {$myObject->x}";

This is also useful in situations where you want to output a variable in the middle of a word:

//will not work
$birthday = 16;
echo "My birthday is on the $birthdayth";

//will work
echo "My birthday is on the {$birthday}th";

Note that { cannot be escaped in a string. If { is followed by $ PHP will assume that you want to parse a variable. To get the literal {$ you must escape it like this:

echo "Curly brace followed by dollar sign: {\$";

//will output
//Curly brace followed by dollar sign: {$

1. Strings and Output in PHP
2. Strings Are Arrays