• Adobe After Effects Expressions

  Random Hexadecimal digits

  Posted by Navarro Parker on November 28, 2012 at 10:52 pm

  I have this expression that will display random hex letters if put into a text layer’s Source Text parameter:

  rate = 5;
seed = Math.floor(time*rate);
seedRandom(seed,true);
String.fromCharCode(65 + Math.floor(random(6)));

  If I lower the starting CharCode from 65 to 48 to include numbers, I get unwanted punctuation symbols from 58~64.

  How can I generate purely hex digits?

  Dan Ebberts replied 13 years, 9 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Dan Ebberts

  November 29, 2012 at 12:09 am

  Try changing the last line to this:

  Math.floor(random(16)).toString(16).toUpperCase();

  Dan
• 

  Navarro Parker

  November 29, 2012 at 2:00 am

  Brilliant as always!

  Can you explain a little bit how that works? Are the symbols being ignored because of the .toUpperCase command? The (16) doesn’t seem to correspond to where the letters are in ASCII table.
• 

  Dan Ebberts

  November 29, 2012 at 2:13 am

  Using 16 as an argument for toString() causes the random integer (0 to 15) to be converted to a hexidecimal (base 16) representation of the number. If you leave off the toUpperCase(), “A” thru “F” will be “a” thru “f”. The ASCII table doesn’t really enter into it.

  Dan

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