Programming PHP

Changing Case
PHP has several functions for changing the case of strings: strtolower( ) and
strtoupper( ) operate on entire strings, ucfirst( ) operates only on the first character
of the string, and ucwords( ) operates on the first character of each word in the
string. Each function takes a string to operate on as an argument and returns a copy
of that string, appropriately changed. For example:
$string1 = "FRED flintstone";
$string2 = "barney rubble";
print(strtolower($string1));
print(strtoupper($string1));
print(ucfirst($string2));
print(ucwords($string2));
fred flintstone
FRED FLINTSTONE
Barney rubble
Barney Rubble
If you’ve got a mixed-case string that you want to convert to “title case,” where the
first letter of each word is in uppercase and the rest of the letters are in lowercase, use
a combination of strtolower( ) and ucwords( ):
print(ucwords(strtolower($string1)));
Fred Flintstone
Encoding and Escaping
Because PHP programs often interact with HTML pages, web addresses (URLs), and
databases, there are functions to help you work with those types of data. HTML,
web page addresses, and database commands are all strings, but they each require
different characters to be escaped in different ways. For instance, a space in a web
address must be written as %20, while a literal less-than sign (