Upgrade to Pro — share decks privately, control downloads, hide ads and more …

The Big "Why equal doesn't equal" Quiz - PHP Serbia

The Big "Why equal doesn't equal" Quiz - PHP Serbia

Presented on May 26t 2019 at the PHP Serbia conference, Belgrade, Serbia.
https://2019.phpsrbija.rs/
---------------------------------------------------------------
Partial slide deck - the actual quiz will not be made public.
---------------------------------------------------------------
So you think you know PHP? But do you really?

We all compare and test data on nearly every other line in our code, be it input validation, an if-statement, a switch or determining what to display and how. So of course we are all experts on how to do these tests and comparisons…. Or are we?

No matter whether you are a beginner or an expert, come and join in the fun for the Big “Why equal doesn’t equal” Quiz, test your knowledge and learn about defensive programming and the quirks of a loose type programming language along the way.
---------------------------------------------------------------
Links:
http://phpcheatsheets.com/
https://github.com/jrfnl/PHP-cheat-sheet-extended

BC Math wrapper: https://gist.github.com/jrfnl/8449978

More Decks by Juliette Reinders Folmer

Other Decks in Programming

Transcript

  1. The Big
    “Why equal doesn’t equal”
    Quiz
    Presented by:
    Juliette Reinders Folmer
    @jrf_nl

    View full-size slide

  2. @jrf_nl
    #PHPSRB
    Who am I?
    • Self-employed independent consultant
    • 15+ years in IT and software development
    • Contributor to LimeSurvey, phpBB, WordPress,
    AdoDB, PHP_CodeSniffer and more

    View full-size slide

  3. Now give yourselves a round of
    applause !!!

    View full-size slide

  4. @jrf_nl
    #PHPSRB
    Some best practices (1)
    • Know your variable types and how type juggling
    works ;-)
    • Always use strict checking unless loose checking
    will avoid code duplication
    • Auto-document your code
    DON’T:
    if ( strpos( $x, $y ) ) {}
    DO:
    if ( strpos( $x, $y ) !== false ) {}

    View full-size slide

  5. @jrf_nl
    #PHPSRB
    Some best practices (2)
    • Make it a habit to test for type AND for what you
    want to know
    • Non-empty string:
    if ( is_string( $x ) && $x !== ‘’ ) {}
    • Non-empty array:
    if ( is_array( $x ) && count( $x ) > 0 ) {}
    or
    if ( is_array( $x ) && $x !== array() ) {}

    View full-size slide

  6. @jrf_nl
    #PHPSRB
    Some best practices (3)
    • Use function_exists(), method_exists() and
    extension_loaded() to write cross-server code
    • Be aware of changes across PHP versions
    • Never be stingy with parentheses ()
    • Avoid $variable contamination
    • isset() and its brother are your friends

    View full-size slide

  7. @jrf_nl
    #PHPSRB
    And remember....
    • ... that what you get from $_POST/$_GET/database
    are strings
    • ... that variable and constant names are
    case-sensitive by default
    • ... that switch() does a loose type check
    • ... that calculations with floats can only be done
    reliably by casting to string and using bcmath
    • ... that ctype_ functions are locale() dependent
    • ... that scalar type declarations will still juggle
    • ... that strict_types declarations are file-based

    View full-size slide

  8. PHPcheatsheets.com
    Contributions welcome:
    https://github.com/jrfnl/PHP-cheat-sheet-extended

    View full-size slide

  9. @jrf_nl
    #PHPSRB
    Want to know more ?

    View full-size slide

  10. Keep in touch!
    Rate this talk: joind.in/talk/c89f8
    Slides: speakerdeck.com/jrf
    Contact me: @jrf_nl

    View full-size slide