There are over 700 functions built into PHP. The following are seven that we used, with examples.
string dirname( string $path); Returns parent directory's path. Often this is used to determine the path to the current script.
Example:
print dirname(__FILE__); // prints something like '/users/me'
string file_get_contents( string $filename [, bool $use_include_path = false [, resource $context [, int $offset = -1 [, int $maxlen ]]]] )Reads an entire file into a string. This is a useful way to read static, non-PHP files. It can even work for downloading remote files, but it's better to tie into the curl functions for serious downloading.
int preg_match( string $pattern , string $subject [, array &$matches [, int $flags = 0 [, int $offset = 0 ]]] )The preceding code performs a regular expression match using Perl-compatible regular expressions.
Example:
if ( preg_match('/^wp_/', $post_type) ){
print 'Post type cannot begin with wp_';
}mixed preg_replace('/[^a-z|_]/', '_', $sanitized['post_type']);Performs a regular expression search and replaces using Perl-compatible regular expressions.
Example:
$string = 'The dog ate my homework'; $pattern = '/dog/i'; $replacement = 'bear'; echo preg_replace($pattern, $replacement, $string);
Returns:
"The bear ate my homework"
mixed print_r( mixed $expression [, bool $return = false ] )Prints human-readable information about a variable. This is extremely useful for debugging.
Example:
$x = array( 'x' => 'Something',
'y' => array('a' => 'alpha')
);
print_r($x);Output:
Array
(
[x] => Something
[y] => Array
(
[a] => alpha
)
)string sprintf( string $format [, mixed $args [, mixed $... ]] )Returns a string produced according to the formatting string format. This function helps to avoid sloppy PHP concatenations. Mostly, we have used only the string types, marked by the %s placeholder, but there are others available. If your format string uses two or more placeholders, you can make use of the syntax for argument-swapping.
Example:
$format = 'The %1$s contains %2$s monkeys'; $output = sprintf($format, 'zoo', 'many');