PHP Programming

PHP ProgrammingIn this video tutorial I’ll teach pretty much the whole PHP programming language in one video. I have received this tutorial request many times lately so I hope you enjoy it. The cheat sheet can be found below the video.

I cover quotes, comments, date(), variables, data types, getting data from HTML, heredoc, constants, arithmetic, shortcuts, reference operators, comparison operators, if, elseif, else, echo, printf, ternary operator, switch, while, for, foreach, arrays, strings, and much more.

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I have other videos like this in which I teach HTML, CSS, JavaScript, and Java in one video if you’re interested.

Code From the Video

enteringinfo.html

<html>
<body>
<form action="learnphp.php" method="post">

<table border="0">

<tr>
	<td>Name</td>
	<td align="center"><input type="text" name="username" size="30" /></td>
</tr>

<tr>
	<td>Address</td>
	<td align="center"><input type="text" name="streetaddress" size="30" /></td>
</tr>

<tr>
	<td>City</td>
	<td align="center"><input type="text" name="cityaddress" size="30"  /></td>
</tr>

<tr>
<td colspan="2" align="center"><input type="submit" value="Submit"/></td>
</tr>

</table>
</form>
</body>
</html>

learnphp.php

<html>

	<head>
		<title>Information Gathered</title>
	</head>
	
	<body>
		
		<!-- 
			You embed PHP code between tags
			echo puts what ever is between quotes in the browser
			
			php code doesn't show if a user tries to view source
			
			A semicolon has to finish every php statement
			
			Single quotes : Print what is between them and ignore 
				escape sequences except for \' and \\
			
			Double quotes : Print many escape sequences, the values
				for variables, and more
		-->
		
		<?php
		
			/* Multiline
				comment */
				
			// Single line comment
			
			# Another single line comment
		
			echo "<p>Data Processed at </p>";
			
			// Define the time zone based on the coordinated universal time
			date_default_timezone_set('UTC');
			
			/* Echos the date
				h : 12 hr format
				H : 24 hr format
				i : Minutes
				s : Seconds
				u : Microseconds
				a : Lowercase am or pm
				l : Full text for the day
				F : Full text for the month
				j : Day of the month
				S : Suffix for the day st, nd, rd, etc.
				Y : 4 digit year
			*/
			echo date('h:i:s:u a, l F jS Y e');
			echo "</p>";
			
			/*
				You store values in variables that have a name
				that starts with a $
				
				Variables can be of any length and contain letters,
				numbers, or underscores
				
				They can't begin with a digit adnd are case sensitive.
				numOfCats is not equal to numofcats
				
				A variable is created and given a data type when it 
				receives a value. That data type can change based on
				if the data is changed.
				
				a. Integer : Whole Numbers
				b. Float : Decimal Numbers
				c. String : Strings or characters
				d. Boolean : true or false
				e. Array : Multiple Items
				f. Object : A Object defined by a class
				
				A variable by default gets the value NULL
				
				You can access values from the html that called
				this php script to execute by putting the name
				assigned in the html in single quotes
				
				The data is stored in an array which is named
				$_POST
			*/
			
			$usersName = $_POST['username'];
			$streetAddress = $_POST['streetaddress'];
			$cityAddress = $_POST['cityaddress'];
			
			echo '<p>Your Information</p>';
			
			// You can combine variables with text using a .
			
			echo $usersName. ' lives at </br>';
			echo $streetAddress. ' in </br>';
			echo $cityAddress. '</br></br>';
			
			/* 
				You can define text using heredoc syntax in the 
				same way you use double quotes.
				Starts with <<< and an identifier that can't be
				used any place else in the text.
				It ends with the identifier and a semicolon
				without any white space or anything else.
			*/
			$str = <<<EOD
			The customers name is
			$usersName and they
			live at $streetAddress
			in $cityAddress</br></br>
EOD;
			
			echo $str;
			
			/* 
				You can define constants thats value can't change
				When we call for a constant we don't use a $ and
				they are normally uppercase
			*/
			define('PI', 3.1415926);
			
			echo "The value of PI is " . PI;
			
			// Arithmetic operators 
			echo "</br></br>5 + 2 = " . (5 + 2);
			echo "</br>5 - 2 = " . (5 - 2);
			echo "</br>5 * 2 = " . (5 * 2);
			
			// You can cast from 1 type to another like this
			echo "</br>5 / 2 = " . (integer) (5 / 2);
			echo "</br>5 % 2 = " . (5 % 2) . "</br></br>";
			
			// Use this shortcut when performing an operation using
			// the same variable +=, -=, *=, /=, %=, .=
			
			$randNum = 5;
			echo $randNum += 5;
			
			echo "</br></br>";
			
			// You can increment and decrement with this shortcut
			
			echo "++randNum = " . ++$randNum . "</br>";
			echo "randNum++ = " . $randNum++;
			
			echo "</br></br>";
			
			/* 
				The reference operator (ampersan / &) can create a
				reference to a variable so if one changes so does the
				other
			*/
			$refToNum = &$randNum;
			$randNum = 100;
			echo '$refToNum = ' . $refToNum;
			
			echo "</br></br>";
			
			// Comparison Operators : ==, !=, <, >, <=, >=
			// === (Equal & Same Type), !== (Not Equal or Same Type)
			// An if block will perform one action or another depending
			// on conditions
			if(5 == 10){
			
				echo '5 = 10';
			
			} else {
			
				echo '5 != 10';
			
			}
			
			echo "</br></br>";
			
			/* 
				elseif is used when you have more conditions to check
			*/ 
			$numOfOranges = 4;
			$numOfBananas = 36;
			
			if(($numOfOranges > 25) && ($numOfBananas > 30)){
			
				echo '25% Discount';
			
			} elseif (($numOfOranges > 30) || ($numOfBananas > 35)){
			
				echo '15% Discount';
			
			} elseif (!(($numOfOranges < 5)) || (!($numOfBananas < 5))){
			
				echo '5% Discount';
			
			} else {
			
				echo 'No Discount For You';
			
			}
			
			echo "</br></br>";
			
			// The ternary operator assigns one or another value
			// depending on the condition 
			// condition ? value if true : value if false
			
			$biggestNum = (15 > 10) ? 15 : 10;
			
			echo 'Biggest Number is ' . $biggestNum;
			
			echo "</br></br>";
			
			// Switch provides different actions depending upon values
			
			switch($usersName) {
			
				case "Derek" :
					echo "Hello Derek";
					break;
					
				case "Sally" : 
					echo "Hello Sally";
					break;
					
				default :
					echo "Hello Valued Customer";
					break;			
			}
			
			echo "</br></br>";
			
			// The while loop performs actions until a condition is met
			
			$num = 0;
			
			while($num < 20){
			
				echo ++$num . ', ';
			
			}
			
			echo "</br></br>";
			
			// The for loop performs actions until a condition is met
			// like the while, but it a compact way
			
			for($num = 1; $num <= 20; $num++){
			
				echo $num;
				
				if($num != 20){
					echo ', ';
				} else {
					break; // or exit() to leave the whole script
				}
			
			}
			
			echo "</br></br>";
			
			// An array can store multiple values
			
			$bestFriends = array('Joy', 'Willow', 'Ivy');
			
			// You can access an item by index starting with 0
			
			echo 'My wife ' . $bestFriends[0];
			
			echo "</br></br>";
			
			// You can add an item by storing in a unused index 
			
			$bestFriends[4] = 'Steve';
			
			echo 'My friend ' . $bestFriends[4];
			
			echo "</br></br>";
			
			// You could cycle through the array with for or foreach
			
			foreach($bestFriends as $friend){
				
				echo $friend . ', ';
			
			}
			
			echo "</br></br>";
			
			// You can create key value pairs in arrays
			
			$customer = array('Name'=>$usersName, 'Street'=>$streetAddress, 'City'=>$cityAddress);
			
			foreach($customer as $key => $value){
			
				echo $key . ' : ' . $value . '</br>';
			
			}
			
			echo "</br></br>";
			
			// You can combine arrays with +
			
			$bestFriends = $bestFriends + $customer;
			
			foreach($bestFriends as $friend){
				
				echo $friend . ', ';
			
			}
			
			// Other common array operators
			// == : Returns true of false if arrays are equal
			// != : Returns if not equal
			// === : Returns if the same items, same order and data type
			
			echo "</br></br>";
			
			// Multidimensional arrays are arrays in arrays
			
			$customers = array(array('Derek', '123 Main', '15212'),
							   array('Sue', '124 Main', '15222'),
							   array('Bob', '125 Main', '15212'));
							   
			for($row = 0; $row < 3; $row++){
			
				for($col = 0; $col < 3; $col++){
				
					echo $customers[$row][$col] . ', ';
				
				}
				echo '</br>';
			
			}
			
			// Common Array Functions
			// sort($yourArray) : Sorts in ascending alphabetical order or 
			// if you add , SORT_NUMERIC or , SORT_STRING
			// asort($yourArray) : sorts arrays with keys
			// ksort($yourArray) : sorts by the key
			// Put a r infront of the above to sort in reverse order
			
			echo "</br></br>";
			
			// Strings store a series of characters
			
			$randString = "         Random String       ";
			
			// You can trim white space with ltrim, rtrim, or trim
			
			echo strlen($randString) . "</br>";
			echo strlen(ltrim($randString)) . "</br>";
			echo strlen(rtrim($randString)) . "</br>";
			echo strlen(trim($randString)) . "</br>";
			
			echo "</br></br>";
			
			// printf allows you to print formatted Strings to the screen
			
			echo "The randomString is $randString </br>";
			
			printf ("The randomString is %s </br>", $randString);
			
			// Coversion codes are useful with decimals
			
			$decimalNum = 2.3456;
			
			printf ("decimal num = %.2f </br>", $decimalNum);
			
			// Other conversion codes
			// b : integer to binary
			// c : integer to character
			// d : integer to decimal
			// f : double to float
			// o : integer to octal
			// s : string to string
			// x : integer to hexadecimal
			
			printf ("10 to binary %b </br>", 10);
			
			echo "</br></br>";
			
			// String case functions
			
			echo strtoupper($randString) . "</br>";
			echo strtolower($randString) . "</br>";
			echo ucfirst($randString) . "</br>";
			
			echo "</br></br>";
			
			// Turning strings into arrays and vice versa
			
			$arrayForString = explode(' ', $randString, 2);
			
			$stringToArray = implode(' ', $arrayForString);
			
			echo "</br></br>";
			
			// Get part of a string
			
			$partOfString = substr("Random String", 0, 6);
			
			echo "Part of String $partOfString </br>";
			
			echo "</br></br>";
			
			// Comparing Strings
			
			$man = "Man";
			$manhole = "Manhole";
			
			// Returns 0 is equal
			// Returns positive if str1 is greater then str2
			// Returns negative if str1 is less than then str2
			// strcasecmp() isn't case sensitive
			
			echo strcmp($man, $manhole) . "</br>";
			
			echo "</br></br>";
			
			// strstr() returns every character after the sting to look for
			// stristr() isn't case sensitive
			
			echo "The String " . strstr($randString, "String") . "</br>";
			
			echo "</br></br>";
			
			// strpos() returns the location for the match
			
			echo "Loc of String " . strpos($randString, "String") . "</br>";
			
			echo "</br></br>";
			
			// str_replace() replaces a string with another
			
			$newString = str_replace("String", "Stuff", $randString)  . "</br>";
			
			echo "New string " . $newString . "</br>";
			
			echo "</br></br>";
			
			// Escaping characters
			
			$dbString = '"Random quotes"';
			
			echo addslashes($dbString) . "</br>";
			echo stripslashes($dbString) . "</br>";
			
			echo "</br></br>";
			
			// Get the data type for a variable
			
			echo 'Data Type for $biggestNum is ' . gettype($biggestNum);
			
			echo "</br></br>";
			
			/* You can check for other types of data with
				is_array : is_bool : is_double : is_int : is_null : 
				is_numeric : is_string
			*/
			
			// empty() returns true or false if a var has a non-zero value
			
			echo 'Does $biggestNum exist ';
			echo empty($biggestNum) ? 'false' : 'true';
			
			echo "</br></br>";
			
			// isset() returns true or false if a variable exists
			
			echo 'Does $biggestNum exist ';
			echo isset($biggestNum) ? 'true' : 'false';
			
			echo "</br></br>";
			
			// You can execute unix commands by surrounding with `s
			echo `ls -la`; // Unix or OSX
			
			// echo `dir /w`; WINDOWS
			
			echo "</br></br>";
			
			/* 
				Functions allow you to reuse code
				A function must begin with a letter, but can contain 
				numbers and underscores
			*/
			
			function addNumbers($num1, $num2){
			
				return $num1 + $num2;
			
			}
			
			echo "3 + 4 = " . addNumbers(3, 4);
			
		?>
		
	</body>
	
</html>

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