Hmm. True. I guess that essentially makes my version the same as sepp2k’s, but meeting the 10-character requirement.

see http://coderrr.wordpress.com/2008/10/28/ruby-golf-generating-random-strings/#comment-809

This clocks in at 34 characters, and does not do upper case, but might inspire some:

i=(x=36)**9;(rand(i*x-i)+i).to_s x

36.

(“%#{rand(2)>0?’x':’X'}”%srand)[9,4]

I’m sure it can be improved upon…

Collaborative golfing is so much funnier than competitive (aka codegolf.com)!

$:.map{rand(?{).chr[/[^_\W]/]||redo}*”

yea i agree in practice you probly wouldn’t run into it much, i wonder what the probability is.

you could shave off one more char i think:

rand.to_s.crypt($0).tr(‘./’,”)[2,9]

or even shorter at the cost of losing all $0 chars and being under 4 more often:

34
rand.to_s.crypt($0).tr(“./#$0″,”)

irb(main):002:0> (1..10000000).map.any? { rand.to_s.crypt($0).delete(‘/.’)[2,9].size < 4 }
=> false

I agree that is a theoretical drawback to the crypt solution I offered. However, it works pretty reliably in practice:

irb(main):001:0> (1..10000000).map.any? { rand.to_s.crypt($0).delete(‘/.’)[2,9].size false

Also, you’ll probably want to make the same correction to your “38″ solution that I suggested for Magnus’s solution earlier. (As it stands, it won’t generate any ‘z’ chars.)