ruby计数用法

1.upto(9){|i| print i, ' ' if i <= 5}
print "\n"


9.downto(1){|i| print i, ' ' if i <= 5}
print "\n"


(1..9).each{|i| print i, ' ' if i <= 5}
print "\n"


1.step(9,1){|i| print i, ' ' if i <= 5}
print "\n"