This is probably off-topic even for #off-topic but, I can specify a string less than 50 chars in length that is alphanumeric with this regex: ^\w{1,50}$ but how do I specify that the string should contain exactly one @?

@jaihindh.reddy unless you are code golfing, just dont use regex

^ for speed?

aww

okay im wrong if you want speed yeah regex

Are you saying regex is faster than your code above?

nope i havent done benchmarks

so i have no clue

regex compiles to some pretty fast fsm though, be hard to beat.

^ yeah

i just suspect it would be

There's faster libs out there though, because java's regex fsm isn't the most optimized.

you could definitely do this if you had direct access to the fsm. But I don't know that regex can express this easily.

well, im in a theory of comp class

hooray college

I would think you’d want the regex that gklijs proposed, plus (<= (count s) 50)

I loved ToC

so i can probably write up a FSM separate from a regex language

and we can manually compile that to a simple regex

That's what I was thinking. \w{a}@\w{b} where (< (+ a b) 50) is not regular grammar. A Context free grammar can represent that of course.

no, it is

that is definitely regular

not in general for any n

but for 50 it is

Oops. My bad. For a general n

since your problem is for 50 though, we can definitely do it

gimmie a few minutes to write something up

I guess

\w{0,0}@{0,49}|\w{0,1}@{0,48}|\w{0,2}@{0,47}|\w{0,3}@{0,46}|\w{0,4}@{0,45}|\w{0,5}@{0,44}|\w{0,6}@{0,43}|\w{0,7}@{0,42}|\w{0,8}@{0,41}|\w{0,9}@{0,40}|\w{0,10}@{0,39}|\w{0,11}@{0,38}|\w{0,12}@{0,37}|\w{0,13}@{0,36}|\w{0,14}@{0,35}|\w{0,15}@{0,34}|\w{0,16}@{0,33}|\w{0,17}@{0,32}|\w{0,18}@{0,31}|\w{0,19}@{0,30}|\w{0,20}@{0,29}|\w{0,21}@{0,28}|\w{0,22}@{0,27}|\w{0,23}@{0,26}|\w{0,24}@{0,25}|\w{0,25}@{0,24}|\w{0,26}@{0,23}|\w{0,27}@{0,22}|\w{0,28}@{0,21}|\w{0,29}@{0,20}|\w{0,30}@{0,19}|\w{0,31}@{0,18}|\w{0,32}@{0,17}|\w{0,33}@{0,16}|\w{0,34}@{0,15}|\w{0,35}@{0,14}|\w{0,36}@{0,13}|\w{0,37}@{0,12}|\w{0,38}@{0,11}|\w{0,39}@{0,10}|\w{0,40}@{0,9}|\w{0,41}@{0,8}|\w{0,42}@{0,7}|\w{0,43}@{0,6}|\w{0,44}@{0,5}|\w{0,45}@{0,4}|\w{0,46}@{0,3}|\w{0,47}@{0,2}|\w{0,48}@{0,1}|\w{0,49}@{0,0}

xD

Oops. Off by one error

yeah i did n=3 and simplifying isnt the easiest task

point being, if it isnt too slow, just take the readable code

regexes as a last resort or a quick hack

yep i give up on simplifying. got a 80 on the midterm for a reason

Came up with this:

(defn valid-VPA? [vpa]
  (and (<= (count vpa) 50)
       (= [\@] (filter #(not (Character/isLetterOrDigit %)) vpa))))

can a vpa be empty?

@(\*\*+\*)+\*(@\*+\*@[email protected])[email protected]

thats for 3

I am not sure what 'vpa' is referring to in that figure, but if by that you mean "a set of states in a nondeterministic finite automata, initially containing only the start state(s), and at each step updated to a new set as symbols of input are consumed", then yes, I think it can become empty, depending on how the state machine is constructed.

its what he called his function

valid-VPA

oh, see it now. oops.

nice catch. Shouldn't be empty

a VPA is like an email and is a unique handle you can transact money using UPI (Unified Payments Interface), something the Indian govt. came up with.

my only issue with your code is that (= [\@] (filter #(not (Character/isLetterOrDigit %)) vpa)) doesn't really read that well

True. I'm writing PHP though for work. And this is far better 🙂

Do you think, a team that adopted Elixir without anyone with significant experience in it, will do the same with ?

I uhhh

i dunno

if there is a business need that is well served then yeah

but "PHP is bad clojure is better" doesn't help the fact that you still have a php codebase you probably cant just throw away

i am in no position to give advice, but first just try introducing it on a small project and see how it goes

We got some near real-time stream processing to do, and Riemann seems like just the thing.