Beginning PHP5 Skim Throughs, Part 1: More on Variables, Operators, and Arrays

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To get further than the tutorial, I'm now going through the somewhat dated 2004 book, Beginning PHP5 by Mercer, et al.  So yay, more random posts on stuff I'm learning.  I know you're so excited!  LOL

Chapter 2 of this book deals with writing simple programs. A lot of the first bit I just skimmed because it was really elementary stuff.  The second half gets into variables and operators.  Obviously I covered some of this in the tutorial, but the book goes a bit more in-depth. 

First, strings. of course, I already did the basic concat operator and looked at strlen() and strpos().  From the book, though, I learned two new tricks: you can use the contact operator in short form, like the + thing and using the strstr() function.

<?php



    $greeting = "My name is ";

    $name = "Inigo Montoya";

    $greeting .= $name;

    echo $greeting;



    echo "<br />";



    echo "Last Name: " . strStr($name, " ");

?>

From there it goes into arithmetic operators.  The basics are kind of "well duh", but it does also go into the special assignment operators (i.e. what I called short form). In particular, it's important to note that the placement does matter!

<?php



    $aNumber = 5;

    $anotherNumber = 10;

    

    echo "<strong>Numbers are 5 and 10</strong><br />";

    $aNumber += $anotherNumber;

    echo "<strong>Add:</strong> " . $aNumber . "<br />";



    $aNumber -= $anotherNumber;

    echo "<strong>Subtract:</strong> " . $aNumber . "<br />";



    $aNumber *= $anotherNumber;

    echo "<strong>Multiply:</strong> " . $aNumber . "<br />";



    $aNumber /= $anotherNumber;

    echo "<strong>Divide:</strong> " . $aNumber . "<br /><br />";

    

    echo "<strong>Base number is</strong> 5<br />";



    $anotherNumber = 5;

    $test1 = ++$anotherNumber;

    echo '<strong>++5</strong> = ' . $test1 . '<br />';



    $anotherNumber = 5;

    $test2 = $anotherNumber++;

    echo '<strong>5++</strong> = ' . $test2 . '<br />';



    $anotherNumber = 5;

    $test3 = --$anotherNumber;

    echo '<strong>--5</strong> = ' . $test3 . '<br />';



    $anotherNumber = 5;

    $test4 = $anotherNumber--;

    echo '<strong>5--</strong> = ' . $test4 . '<br />';

?>

Then to arrays again.  Mostly picking up more array functions here versus the tutorial.

<?php



    $mybooks = array();

    $mybooks[] = "D.N.Angel, Volume 12";

    $mybooks[] = "Spice &amp; Wolf, Volume 07: Side Colors";

    $mybooks[] = "Kieli, Volume 07: As the Deep Ravine's Wind Howls";

    $mybooks[] = "Book Girl and the Corrupted Angel (Book 4)";

    $mybooks[] = "Ultra Cute, Volume 09";

    $mybooks[] = "D.N.Angel, Volume 12";

    

    echo "I have " . count($mybooks) . " books in my array.<br />";

    

    if (count(array_count_values($mybooks)) != count($mybooks)) {

        echo "There is a duplicate entry in my array....fix please, or better yet I will.  Here's what I had:<br />";

        echo "<pre>";

        print_r (array_count_values($mybooks));

        echo "</pre>";

        $mybooks = array_unique($mybooks);

    }

    

    $pets = array();

    $pets["Border Collie Mix"] = "Yuki";

    $pets["Australian Shepherd Mix"] = "Blue";

    $pets["Domestic Medium Hair"] = "Fusion";

    

    echo "Pets:<br />";

        echo "<pre>"; 

        print_r ($pets);

        echo "</pre>";



    echo "And flipped it<br />";

        echo "<pre>"; 

        print_r (array_flip($pets));

        echo "</pre>";

    

    echo "ASorted...";

        echo "<pre>"; 

        asort($mybooks);

        print_r ($mybooks);

        echo "</pre>";



    echo "vs regular Sorted...";

        echo "<pre>"; 

        sort($mybooks);

        print_r ($mybooks);

        echo "</pre>";

?>

Count unique values is cool, especially since I quickly realized I could use it as I did in my example to indicate a duplicate value has been found.  Array_flip() is interesting though I'm not sure what practical usage it will have.  ASorted is a good one to remember since it keeps the index values!

Note: I've realized that there is a bug in the SyntaxHighlighter causing it to blank out the BR tags from my code.  So if you see echo "" it is supposed to be echo "<br /><br />" and many of the other blank "" at in the concatenated strings are actually "<br />".  So far I haven't found a fix as the code, and while this bug was report on the developer's GitHUb 2 years ago, he has never responded.