Useful string functions

string_funcs.php

/**
 * Useful string functions 
 */

/**
 * Replace any whitespace character or sequence of whitespace characters into a single space
 *
 * @param	string	$str
 * @return	string	$str with any sequence of whitespace collapsed into a single space
 */
function collapse_whitespace($str) {
	return preg_replace('/\\s+/', ' ', $str);
}

/**
 * Remove or replace known problematic characters 
 * 
 * 	xA0 = newline
 * 	x00 = NULL (which could be interpretted as end of string)
 *
 * @param	string	$str
 * @param	string	$replacement	What to use as a replacement. Optional. Default is an empty string (i.e., remove).
 * @return	string	$str without known problem characters replaced/removed.
 */
function remove_problem_characters($str, $replacement = '') {
	return strtr((string)$str, array("\xa0" => $replacement, "\x00" => $replacement));
}