Page 126 - Beginning PHP 5.3

Part II: Learning the Language
To convert a string to all lowercase, use strtolower() . This function takes a string to convert, and
returns a converted copy of the string:
$myString = “Hello, world!”;
echo strtolower( $myString ); // Displays ‘hello, world!’

Similarly, you can use strtoupper() to convert a string to all uppercase:

$myString = “Hello, world!”;
echo strtoupper( $myString ); // Displays ‘HELLO, WORLD!’

ucfirst() makes just the first letter of a string uppercase:
$myString = “hello, world!”;
echo ucfirst( $myString ); // Displays ‘Hello, world!’

lcfirst() – – introduced in PHP 5.3 — makes the first letter of a string lowercase:
$myString = “Hello, World!”;

echo lcfirst( $myString ); // Displays ‘hello, World!’
Finally, ucwords() makes the first letter of each word in a string uppercase:
$myString = “hello, world!”;
echo ucwords( $myString ); // Displays ‘Hello, World!’

Speaking of upper - and lowercase, most of the search and replacement functions described earlier in the
chapter are case - sensitive . This means that they ’ ll only match letters of the same case. For example:

$myString = “Hello, world!”;
// Displays “Not found”
if ( strstr( $myString, “hello” ) )
echo “Found”;
else

echo “Not found”;
However, PHP includes case - insensitive versions of many string functions, which means they ’ ll work
even if the case of the strings don ’ t match. For example, there ’ s a case - insensitive version of strstr() ,
called stristr() :

$myString = “Hello, world!”;
// Displays “Found”
if ( stristr( $myString, “hello” ) )
echo “Found”;
else

echo “Not found”;

88

9/21/09 8:53:45 AM
c05.indd 88
c05.indd 88 9/21/09 8:53:45 AM