PHP Tutorials


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PHP Tutorials

  1. 1. PHP Basic Basic PHP Syntax PHP Arrays PHP If...Else Statements PHP For Loops PHP Forms and User Input PHP Functions PHP introduction PHP Operators PHP - Variables PHP While Loops
  2. 2. Basic PHP Syntax <ul><ul><li>PHP code is executed on the server , and the plain HTML result is sent to the browser. A PHP scripting block can be placed anywhere in the document. It always starts with <?php and ends with ?>. </li></ul></ul><ul><ul><li>The example of PHP code below sends the text “Conkurent LLC” to the browser: </li></ul></ul><ul><ul><li><html> </li></ul></ul><ul><ul><li>  <body> </li></ul></ul><ul><ul><li>  <?php   echo &quot; Conkurent LLC&quot;;   ?>   </li></ul></ul><ul><ul><li></body>   </li></ul></ul><ul><ul><li></html>   </li></ul></ul><ul><ul><li>To make a single-line comment, use //. To make a large comment block, use /* and */. See the example below:   </li></ul></ul><ul><ul><li><html> </li></ul></ul><ul><ul><li>  <body> </li></ul></ul><ul><ul><li>  <?php   //This is a comment   /*   This is   a comment   block   */   ?> </li></ul></ul><ul><ul><li>  </body>   </li></ul></ul><ul><ul><li></html> </li></ul></ul>
  3. 3. PHP Arrays <ul><ul><li>An array is a special variable that stores one or more values in a single variable. </li></ul></ul><ul><ul><li>If you have a list of items, storing them in single variables could look like this: </li></ul></ul><ul><ul><li>$item1=&quot;item-name1&quot;; </li></ul></ul><ul><ul><li>$item2=&quot; item-name2&quot;; </li></ul></ul><ul><ul><li>$item3=&quot; item-name3&quot;; </li></ul></ul><ul><ul><li>An array can hold all your variable values under a single name. And you can access the values by referring to the array name. Each element in the array has its own index so that it can be easily accessed. </li></ul></ul><ul><ul><li>In PHP, there are three kind of arrays: </li></ul></ul><ul><ul><ul><li>Numeric array - An array with a numeric index </li></ul></ul></ul><ul><ul><ul><li>Associative array - An array where each ID key is associated with a value </li></ul></ul></ul><ul><ul><ul><li>Multidimensional array - An array containing one or more arrays </li></ul></ul></ul>
  4. 4. PHP If…Else Statements <ul><ul><li>Conditional statements are used to perform different actions based on different conditions. Use the if....else statement to execute some code if a condition is true and another code if a condition is false . </li></ul></ul><ul><ul><li>Syntax </li></ul></ul><ul><ul><li>if (condition) code </li></ul></ul><ul><ul><li>to be executed if condition is true ; </li></ul></ul><ul><ul><li>else code to be executed if condition is false ; </li></ul></ul>
  5. 5. <ul><ul><li>The following example will output &quot;Get ready for the week!&quot; if the current day is Monday, otherwise it will output &quot;Have a good day!&quot;: </li></ul></ul><ul><ul><li><html> </li></ul></ul><ul><ul><li><body> </li></ul></ul><ul><ul><li><?php $d=date(&quot;D&quot;); </li></ul></ul><ul><ul><li>if ($d==&quot;Mon&quot;) echo &quot; Get ready for the week!&quot;; </li></ul></ul><ul><ul><li>else echo &quot;Have a good day!&quot;; ?> </li></ul></ul><ul><ul><li></body> </li></ul></ul><ul><ul><li></html> </li></ul></ul>
  6. 6. <ul><ul><li>Use the if....elseif...else statement to select one of several blocks of code to be executed. </li></ul></ul><ul><ul><li>Syntax </li></ul></ul><ul><ul><li>if (condition)   </li></ul></ul><ul><ul><li>code to be executed if condition is true ;   </li></ul></ul><ul><ul><li>elseif (condition)   </li></ul></ul><ul><ul><li>code to be executed if condition is true ;   </li></ul></ul><ul><ul><li>else   </li></ul></ul><ul><ul><li>code to be executed if condition is false ; </li></ul></ul>
  7. 7. PHP For Loops <ul><ul><li>The for loop is simply a while loop with a bit more code added to it. The common tasks that are covered by a for loop are: </li></ul></ul><ul><ul><ul><li>Set a counter variable to some initial value. </li></ul></ul></ul><ul><ul><ul><li>Check to see if the conditional statement is true. </li></ul></ul></ul><ul><ul><ul><li>Execute the code within the loop. </li></ul></ul></ul><ul><ul><ul><li>Increment a counter at the end of each iteration through the loop. </li></ul></ul></ul><ul><ul><li>Syntax </li></ul></ul><ul><ul><li>for (init; condition; increment) </li></ul></ul><ul><ul><li>{ </li></ul></ul><ul><ul><li>code to be executed; </li></ul></ul><ul><ul><li>} </li></ul></ul><ul><ul><li>Parameters: </li></ul></ul><ul><ul><ul><li>init : Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop) </li></ul></ul></ul><ul><ul><ul><li>condition : Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends. </li></ul></ul></ul><ul><ul><ul><li>increment : Mostly used to increment a counter (but can be any code to be executed at the end of the loop) </li></ul></ul></ul>
  8. 8. PHP Forms and User Input <ul><ul><li>The example below contains an HTML form with two input fields and a submit button: </li></ul></ul><ul><ul><li>< html > </li></ul></ul><ul><ul><li>< body > </li></ul></ul><ul><ul><li>< form action=&quot;welcome.php&quot; method=&quot;post&quot;> </li></ul></ul><ul><ul><li>Name: < input type=&quot;text&quot; name=&quot;fname&quot; /> </li></ul></ul><ul><ul><li>Age: < input type=&quot;text&quot; name=&quot;age&quot; /> </li></ul></ul><ul><ul><li>< input type=&quot;submit&quot; /> </li></ul></ul><ul><ul><li></ form > </li></ul></ul><ul><ul><li></ body > </li></ul></ul><ul><ul><li></ html > </li></ul></ul>
  9. 9. <ul><ul><li>When a user fills out the form above and clicks on the submit button, the form data is sent to a PHP file, called &quot;welcome.php&quot;, &quot;welcome.php&quot; looks like this: </li></ul></ul><ul><ul><li><html> </li></ul></ul><ul><ul><li><body> </li></ul></ul><ul><ul><li>Welcome <?php echo $_POST[&quot;fname&quot;]; ?> !<br /> </li></ul></ul><ul><ul><li>You are <?php echo $_POST[&quot;age&quot;]; ?> years old. </li></ul></ul><ul><ul><li></body> </li></ul></ul><ul><ul><li></html> </li></ul></ul><ul><ul><li>Output could be something like this: Welcome John! </li></ul></ul><ul><ul><li>You are 28 years old. </li></ul></ul><ul><ul><li>Notice that any form element in an HTML page will automatically be available to your PHP scripts. </li></ul></ul>
  10. 10. PHP Functions <ul><ul><li>In PHP, there are more than 700 built-in functions . </li></ul></ul><ul><ul><li>This chapter shows how to create your own functions . A function will be executed by a call to the function. You may call a function from anywhere within a page. </li></ul></ul><ul><ul><li>Syntax </li></ul></ul><ul><ul><li>function functionName() </li></ul></ul><ul><ul><li>{ </li></ul></ul><ul><ul><li>code to be executed; </li></ul></ul><ul><ul><li>} </li></ul></ul>
  11. 11. <ul><ul><li>To add more functionality to a function, you can add parameters. A parameter is just like a variable. </li></ul></ul><ul><ul><li>Parameters are specified after the function name, inside the parentheses. </li></ul></ul><ul><ul><li>To let a function return a value, use the return statement (see the example below): </li></ul></ul><ul><ul><li>  <html> </li></ul></ul><ul><ul><li><body> </li></ul></ul><ul><ul><li><? </li></ul></ul><ul><ul><li>php function add($x,$y) </li></ul></ul><ul><ul><li>{ </li></ul></ul><ul><ul><li>$total=$x+$y; return $total; </li></ul></ul><ul><ul><li>} </li></ul></ul><ul><ul><li>echo &quot;6 + 9 = &quot; . add(6,9); </li></ul></ul><ul><ul><li>?> </li></ul></ul><ul><ul><li></body> </li></ul></ul><ul><ul><li></html> </li></ul></ul><ul><ul><li>Output: 6 + 9 = 15 </li></ul></ul>
  12. 12. <ul><ul><li>Arithmetic Operators </li></ul></ul><ul><ul><li>OperatorDescriptionExampleResult +Additionx=2 x+24-Subtractionx=2 5-x3*Multiplicationx=4 x*520/Division15/5 5/23 2.5%Modulus (division remainder)5%2 10%8 10%21 2 0++Incrementx=5 x++x=6--Decrementx=5 x--x=4 </li></ul></ul>