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The Truth About Truthy & Falsy

Avatar for Swaroop SM Swaroop SM
April 10, 2015
Technology
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57

The Truth About Truthy & Falsy

Deck demonstrating which values are truthy / falsy w.r.t a programming language.

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Swaroop SM

April 10, 2015
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Transcript

  1. WTF (What’s Truthy Falsy) Swaroop SM Cybrilla Technologies

  2. - TRUTHY: If the value isn’t literally “true” but evaluates

    to true. - FALSY: If the value isn’t literally “false” but evaluates to false. What is it?

  3. undefined 0 false “” null NaN nil [] {} true

    True False None

  4. var a = 0; if(a) { alert(“I’m TRUTHY :)”); }

    else { alert(“I’m FALSY. Feel so proud. :D”); } The Confusion

  5. TRUTHY - true - 0 - “” - [] -

    {} Ruby FALSY - false - nil

  6. Ruby on Rails present? - !blank? - 0 - true

    blank? - nil - “” - [] - {} - false - whitespace

  7. Python TRUTHY - True - 1 FALSY - False -

    None - 0 - [] - “” - {}

  8. JavaScript TRUTHY - true - “0” - [] - {}

    FALSY - 0 - false - “” - undefined - null - NaN

  9. Thank You! @smswaroop http://www.github.com/swaroopsm/truthy-falsy