Common PHP Functions

function countWords($words) {
	$result = array();
 
	$unique = array_unique($words);
	$unique = array_values($unique);
 
	// loop through the unique words to count them in the original words
	for($x = 0; $x < count($unique); $x++) {
		$result[0][$x] = $unique[$x];
		$result[1][$x] = 0;
		
		foreach($words as $w) {
			if($unique[$x] == $w) {
				$result[1][$x] += 1;
			}
		}
	}
	
	return $result;
}

function getWords($string) {
	$words = explode(' ', trim($string));
	
	foreach($words as $key=>$word) {
		$last_char = $word[strlen($word)-1];
		$punctuations = '.;:!?,';
		
		// remove any punctuations or chracters from the end of the word
		$words[$key] = rtrim($word, $punctuations);
	}
	
	return $words;
}

function getSentences($string) {
	preg_match_all('~.*?[?.!]~s', $string, $sentences);
	
	return array_map('trim', $sentences[0]);
}

function capitalizeWords($words = array(), $str) {
	if(!empty($words) && $str != '') {
		foreach($words as $word) {
			$str = str_replace($word, ucwords($word), $str);
		}
	}
	
	return $str;
}

function ipAddress() {
return $_SERVER['REMOTE_ADDR'];
}

function getColorShade($color) {
	$colors = array();
	
	for($x = 0; $x < 255; $x++) {
		$c = '';
		
		switch($color) {
			case 'red':
				$c = dechex($x).'0000';
			break;
			case 'green':
				$c = '00'.dechex($x).'00';
			break;
			case 'blue':
				$c = '0000'.dechex($x);
			break;
			default:
				$c = '000000';
		}
		
		if(strlen($c) < 6) {
			$c .= '0';
		}
		$colors[$x] = $c;
	}
	
	// remove duplicates and reset the indexes
	$colors = array_unique($colors);
	$colors = array_values($colors);
	
	sort($colors);
	
	return $colors;
}

function camelizeString($string) {
	$string = trim($string);
	$result = '';
	$space_found = (strpos($string, ' ') !== FALSE); // 1 or more spaces found in the string
	$underscore_found = (strpos($string, '_') !== FALSE); // 1 or more underscores found in the string
 
	if($space_found || $underscore_found) {
		if($space_found && $underscore_found) {
			$split_str = split('[ _]', $string);
		} else if($space_found) {
			$split_str = split(' ', $string);
		} else if($underscore_found) {
			$split_str = split('_', $string);
		}
		
		$result = strtolower($split_str[0]);
		for($x = 1; $x < count($split_str); $x++) {
			$result .= ucwords($split_str[$x]);
		}
	} else {
		$result = strtolower($string);
	}
	
	return $result;
}

function humanizeString($string) {
return str_replace('_', ' ', $string);
}

function underscoreString($string) {
return str_replace(' ', '_', $string);
}

function jsRedirect($url) {
	?>
	<script type="text/javascript">
	window.location = "<?php echo $url; ?>";
	</script>
	<?php
}

function filterURL($url) {
	if(strpos($url, 'http://') !== FALSE) {
		return $url;
	} else {
		if($url == '') {
			return '';
		} else {
			return 'http://'.$url;
		}
	}
}

function isWeekday($date) {
	$d = date('w', strtotime($date));
	
	if($d != 6 && $d != 0)
		return TRUE;
	else
		return FALSE;
}

function isWeekend($date) {
	$d = date('w', strtotime($date));
 
	if($d == 6 || $d == 0)
		return TRUE;
	else
		return FALSE;
}

function removeCharacters($char, $subject) {
	$subject = str_replace($char, '', $subject);
	
	return $subject;
}

function filterWords($words = array(), $filter_str, $subject) {
	foreach($words as $word) {
		$subject = str_replace($word, $filter_str, $subject);
	}
	
	return $subject;
}

function truncateWords($subject, $word_ct) {
	$str_word_count = str_word_count($subject);
	
	if($str_word_count < $word_ct) {
		return $subject;
	} else {
		$words = split(' ', $subject);
		$result_str = '';
		
		for($x = 0; $x < $word_ct; $x++) {
			$result_str .= $words[$x].' ';
		}
		
		return trim($result_str);
	}
}

function checkDuplicates($subject) {
	$words = split(' ', $subject);
	$temp = array();
	$duplicates = array();
	
	if(!empty($words)) {
		foreach($words as $word) {
			if(in_array($word, $temp)) {
				if(!in_array($word, $duplicates)) {
					$duplicates[] = $word;
				}
			} else {
				$temp[] = $word;
			}
		}
	}
	
	return $duplicates;
}

function repeat($str, $number) {
	for($x = 0; $x < $number; $x++) {
		echo $str;
	}
}

function averageWordCount($strings = array()) {
	$word_ct = 0;
 
	if(!empty($strings)) {
		for($x = 0; $x < count($strings); $x++) {
			$word_ct += str_word_count($strings[$x]);
		}
		
		return $word_ct/count($strings);
	} else {
		return 0;
	}
}

function averageCharCount($str) {
	$char_ct = 0;
	
	if($str != '') {
		$words = split(' ', trim($str));
		for($x = 0; $x < count($words); $x++) {
			$char_ct += strlen($words[$x]);
		}
		
		return $char_ct/count($words);
	} else {
		return 0;
	}
}

function areaOfTriangle($base, $height) {
return ($base * $height) / 2;
}

function circumferenceOfCircle($diameter) {
return pi() * $diameter;
}

function areaOfCircle($radius) {
return pi() * ($radius * $radius);
}

function redirect($url) {
header('Location: '.$url);
}

function validateEmail($email) {
	if(preg_match('/^[^@]+@[^@.]+\.[^@]*\w\w$/', $email)) {
		return TRUE;
	} else {
		return FALSE;
	}
}

function generateRandomCode($length) {
	$code = '';
	
	$possible = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
	
	for($x = 0; $x < $length; $x++) {
		$random = mt_rand(0, strlen($possible)-1);
		
		$code .= $possible[$random];
	}
	
	return $code;
}

function decrypt($key, $encrypted_str) {
	$decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($encrypted_str), MCRYPT_MODE_CBC, md5(md5($key))), "\0");
	
	return $decrypted;
}

function encrypt($key, $str) {
	$encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $str, MCRYPT_MODE_CBC, md5(md5($key))));
	
	return $encrypted;
}

function convertDate($date) {
return date('F d, Y', strtotime($date));
}

function getRandomChar($str, $exclude_spaces = TRUE) {
	$random_num = mt_rand(0, strlen($str)-1);
	$random_char = $str[$random_num];
	
	if($exclude_spaces) {
		if($random_char == ' ') {
			$random_char = getRandomChar($str, $exclude_spaces);
		}
	}
	
	return $random_char;
}

function getTimeDiff($start, $end) {
	$uts['start'] = strtotime($start);
	$uts['end'] = strtotime($end);
	if($uts['start'] !== -1 && $uts['end'] !== -1) {
		if($uts['end'] >= $uts['start']) {
			$diff = $uts['end'] - $uts['start'];
			if($days=intval((floor($diff/86400))))
				$diff = $diff % 86400;
			if($hours=intval((floor($diff/3600))))
				$diff = $diff % 3600;
			if($minutes=intval((floor($diff/60))))
				$diff = $diff % 60;
			$diff = intval($diff);            
			return(array('days'=>$days, 'hours'=>$hours, 'minutes'=>$minutes, 'seconds'=>$diff));
		} else {
			trigger_error("Ending date/time is earlier than the start date/time", E_USER_WARNING);
		}
	} else {
		trigger_error("Invalid date/time data detected", E_USER_WARNING);
	}
	
	return(FALSE);
}

function calcFactorial($number) {
	$result = 1;
 
	for($x = 1; $x <= $number; $x++) {
		$result *= $x;
	}
	
	return $result;
}

function calcFOIL($a, $b, $c, $d) {
	$first = $a*$c;
	$outer = $a*$d; // x
	$inner = $b*$c; // x
	$last = $b*$d; // x^2
	
	return $last.'x<sup>2</sup> '.($outer+$inner).'x '.$first;
}

function getEfficiency($horsepower, $watts) {
return round((746 * $horsepower) / $watts, 4);
}

function getVoltage($current, $resistance) {
return round($current * $resistance, 4);
}

function getResistance($voltage, $current) {
return round($voltage / $current, 4);
}

function getCurrent($voltage, $resistance) {
return round($voltage / $resistance, 4);
}

function getWatts($voltage, $current) {
return round($voltage * $current, 4);
}

function convertTemperature($temp) {
	$result = 0;
 
	// get the temperature unit
	$unit = strtolower($temp[(strlen($temp)-1)]);
	$number = substr($temp, 0, (strlen($temp)-1));
	
	switch($unit) {
		case 'c':
			$result = ($number * 1.8) + 32;
		break;
		case 'f':
			$result = ($number - 32) * 1.8;
		break;
		default:
			return FALSE;
		break;
	}
	
	return $result;
}

function flipCoin() {
	$possible = array('heads', 'tails');
	
	$key = array_rand($possible);
	
	return $possible[$key];
}

function randomColor() {
	$color = '';
	
	for($x = 0; $x < 3; $x++) {
		$rand_hex = dechex(rand(0, 255));
		
		// check if the value is only one digit
		// if so, prepend zero to it
		if(strlen($rand_hex) < 2) {
			$rand_hex = '0'.$rand_hex;
		}
		
		$color .= $rand_hex;
	}
	
	return '#'.$color;
}

function averageDifference($numbers = array()) {
	if(!empty($numbers)) {
		sort($numbers);
		
		$differences = array();
		
		// loop through the numbers and find the differences
		for($x = (count($numbers)-1); $x >= 0; $x--) {
			if(is_numeric($numbers[$x])) {
				// check if there is a next number to subtract
				if($x != 0) {
					$differences[] = $numbers[$x]-$numbers[($x-1)];
				}
			}
		}
		
		// now we simply get the average of the differences if the previous loop was successful
		if(!empty($differences)) {
			$sum = array_sum($differences);
			
			return round($sum / count($differences), 4);
		} else {
			return FALSE;
		}
	} else {
		return FALSE;
	}
}

function validateNumber($string, $min = 1, $max = 99) {
	if(!is_numeric($string)) {
		return FALSE;
	} else {
		if($string < $min || $string > $max) {
			return FALSE;
		}
	}
	
	return TRUE;
}

function getRGB($hexidecimal) {
	$hexidecimal = str_replace('#', '', $hexidecimal);
 
	$chunks = str_split($hexidecimal, 2);
	
	// convert to decimal
	foreach($chunks as $key=>$val) {
		$chunks[$key] = hexdec($val);
	}
	
	return array('red'=>$chunks[0], 'blue'=>$chunks[1], 'green'=>$chunks[2]);
}

function sumSeries($min = 1, $max = 100) {
	$result = 0;
	
	for($x = $min; $x <= $max; $x++) {
		$result += $x;
	}
	
	return $result;
}

function scrambleString($string) {
	$str1 = '';
	$str2 = '';
	$i = 0;
	$x = 0;
	$string = explode(' ', $string);
	$result = '';
 
	for ($x = 0; $x < strlen($string); $x++) {
		$tmp = $string[$x];
		srand((double) microtime() * 10000000);
		
		for ($i = 0; $i < strlen($tmp); $i++) {
			$str1 = rand(0, strlen($tmp) - 1);
			$str2 = $tmp[$i];
			$tmp[$i] = $tmp[$str1];
			$tmp[$str1] = $str2;
		}
		
		$result .= ' '.$tmp;
	}
	
	return $result;
}

function rollDice($number_of_dice = 2) {
	$results = array();
 
	for($x = 0; $x < $number_of_dice; $x++) {
		$results[] = rand(1, 6);
	}
	
	return $results;
}

function getAge($birthday) {
	$seconds_in_year = (24*60*60)*365;
 
	return floor((time() - strtotime($birthday))/$seconds_in_year);
}