PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

116 Chapter 4 String Manipulation and Regular Expressions
If you see this result, it means that your configuration of PHP is set up to add and strip
slashes automatically.This capability is controlled by the magic_quotes_gpc configuration
directive in its name.The letters gpc, which is turned on by default in new installations
of PHP, stand for GET, POST, and cookie.This means that variables coming from
these sources are automatically quoted.You can check whether this directive is switched
on in your system by using the get_magic_quotes_gpc() function, which returns true
if strings from these sources are being automatically quoted for you. If this directive is on
in your system, you need to call stripslashes() before displaying user data; otherwise,
the slashes will be displayed.
Using magic quotes allows you to write more portable code.You can read more
about this feature in Chapter 24, “Other Useful Features.”
Joining and Splitting Strings with String
Functions
Often, you may want to look at parts of a string individually. For example, you might
want to look at words in a sentence (say, for spellchecking) or split a domain name or
email address into its component parts. PHP provides several string functions (and one
regular expression function) that allow you to do this.
In the example, Bob wants any customer feedback from bigcustomer.com to go
directly to him, so you can split the email address the customer typed into parts to find
out whether he or she works for Bob’s big customer.
Using explode(), implode(), and join()
The first function you could use for this purpose, explode(), has the following prototype:
array explode(string separator, string input [, int limit]);
This function takes a string input and splits it into pieces on a specified separator
string.The pieces are returned in an array.You can limit the number of pieces with the
optional limit parameter.
To get the domain name from the customer’s email address in the script, you can use
the following code:
$email_array = explode(‘@’, $email);
This call to explode() splits the customer’s email address into two parts: the username,
which is stored in $email_array[0], and the domain name, which is stored in