Recursively cycle through an array in a loop

Tuesday, 20 April 2010 12:55

The following code recursively loops through an array providing we add a conditional statement e.g.



def cycle(a, i=0)

  puts a.join

  cycle(a + [a.shift], i+1) if i < 20

end



cycle '10000'.split(//).map &:to_s

output:



# or 



c2 =->(x,i=0){p x.join; d.call x+[x.shift],i+1 if i<20}

c2.call '10000'.split(//).map &:to_s



# or



def c3(a,i=0); p a.join; c3(a+[a.shift],i+1) if i<20 end

c3 '10000'.split(//).map &:to_s



# or without recursion

out = 10.times.map {a = a[1..-1] + [a[0]]}

# or

out = 10.times.map {a[1..-1].concat [a[0]]}

# or

out = (0..10).map {a[1..-1].concat [a[0]]}

Notes:
1) While attempting an infinite loop within irb1.9.1 an error occurred after ... 7656 levels...
2) While attempting an infinite loop within cycle.rb the following error was observed after 7693 levels "cycle': stack level too deep (SystemStackError)"