[MERGE] rand_chars() optimization

[John Arbash Meinel]

John Arbash Meinel has voted +1 (conditional).
Status is now: Semi-approved
Comment:
I have to wonder why you are doing 20 characters in one pass, and 16 in 
the other. Also, I'd like to see it more like 50,000 rather than 
100,000. It just seems that you have a fairly fast system, and it is 
still above the 1s target time.

As far as the concern between the for loop and a list comprehension... 
I'm guessing that Jython would be different than CPython (cpython 
explicitly has support for replacing strings in place, which is 
special).

I don't think the 30ms difference you are seeing is meaningful, but I'm 
guessing regardless the form, it is going to be faster than the original 
implementation.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C45F448B2.5070901%40hlabs.spb.ru%3E