PHP Start

• I am working from
  • The Wikibooks PHP Tutorial
• Examples are in ~dbennett/313/php
• Hello world

  <?php
  	print "hello world\n";
  ?>
      

• Actions are within a php tag
• Look at this page
• My web server is configured to interpret php in a file.php
• Statements are terminated with a ;
• print or echo
• . is string concatenation
• Strings are marked wtih '' or ""
  • ' literal $var' - will use the literal $var
  • " literal $var" - will dereference $var
• Variables
  • php is dynamically-typed
    • Store whatever you want wherever you want.
  • Start with a $
  • Case sensitive
  • Look at hi.php or this page
  • $this is special
  • Undefined value depends on context
    • Integers, floats ← 0
    • Bool ← False
    • String ← ""
  • Scope rules appear to follow C++
  • static as in c++
  • Variable Variables
    • $a = "hello"
    • $$a = "world";
    • $hello is now "world"
• Comments as in c/c++ (// and /* */)
• Look at vars.php or this page
• Arrays
  • More like maps or dictionaries or even hash tables.
  • $myList = array("Monday", "Tuesday", 1+2, $thursday);
  • But add to them too
  • $myList[4] = "Friday too!";
  • Or even $myList['Hello'] = 'Saturday';
  • Since I refuse, loops
    • for as in c/c++

    • for ($i=0;$i< count($myList);$i++) {
            print $i.": ".$myList[$i].$eoln;
      }
      
      	       

    • Foreach, sort of like python

      
      foreach ($myList as $listItem) {
           print $listItem.$eoln;
      }
      	       

    • Or even

      foreach (array_keys($myList) as $i) {
          print $i.": ".$myList[$i].$eoln;
      }
      

  • Look at array.php or this page
• Other control structures
  • if and swtich like c/c++ (sort of)
    • if, elseif, else
  • while as in C/C++
  • do while as in c/c++