p5.js changing data types (from float into int)

Answers

• GoToLoop

  October 2016 edited October 2016 Answer ✓

  Use unary operator ~ 2x: imgNum = ~~random(14);. :ar!
  There are some other approaches too. ;;)
  For example the | operator: imgNum = random(14) | 0; or imgNum = 0 | random(14);.
• GoToLoop

  October 2016

  The article below is about transitioning Processing's Java Mode to p5.js: :bz
  https://GitHub.com/processing/p5.js/wiki/Processing-transition
• jeremydouglass

  October 2016 edited October 2016

  @beccarose -- change a float into an int with int() -- use this if you want your code to be simple and clear. See the p5.js int reference page:

  int(): Converts a boolean, string, or float to its integer representation.

  ---

  Using -- or | 0 is indeed very " :ar! "

  They are not intended for this purpose -- but they are efficient ways to force the answer to be an int as a side-effect of doing something different (integer subtraction bitwise not, or a logical "or" test).
• GoToLoop

  October 2016 edited October 2016

  Using -- or | 0 is indeed very :ar! .
  (integer subtraction, ...

  It's not the decrement operator --, but 2 Bitwise NOT tildes: ~~: :-\"
  https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_Operators#Bitwise_NOT

  BtW, we can replace | 0 w/ & -1 too: imgNum = random(14) & -1;
  Also imgNum = random(14) >> 0;, imgNum = random(14) >>> 0;, imgNum = random(14) << 0;, etc. :P

  And other more conservative options below if you prefer: :-B

  1. https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt
  2. https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseInt
  3. https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor
  4. https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/trunc
• beccarose

  October 2016 edited October 2016

  @jeremydouglass would you be able to provide a specific example. I have converted types in other languages, but p5.js only uses var, so not sure how using int() would work in that case?
• beccarose

  October 2016

  @GoToLoop thanks I'll give those a go tonight
• beccarose

  October 2016 edited October 2016

  @GoToLoop just tried the "pirate" way 2x tildes and worked really well. thank you!

  (note in Bristol my home town we are really into pirates...oooh-argh!)
• GoToLoop

  October 2016 edited October 2016

  ... but p5.js only uses var, ...

  Although variables in the JS language don't have types, the data they store DO! L-)
  And it's misinformation that var is the only way to declare variables in JS. Actually there are 5: @-)

  1. var: https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/var
  2. let: https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let
  3. const: https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const
  4. function: https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function
  5. class: https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/class

  I bet you're finding strange that function & class are also variable declarations. >-)
  But when not using their anonymous expression form, rather their declaration form, they do create a variable! ;;)
• jeremydouglass

  October 2016

  @beccarose -- the forum formatting may have hidden the fact that my answer linked to the p5.js int() reference page, which also gives many examples:

  print(int(10.31)); // 10
  
• blindfish

  October 2016

  (note in Bristol my home town we are really into pirates...oooh-argh!)

  @beccarose - in which case you must know of Pirate Pete :ar! :D :ar!