How come the outcome to this is 'a' the if statement should completely be skipped tbh (it's falsey?). ? Being there is no str[i-1] on the first iteration, it should throw an error, but it doesn't? When i trace through the steps using ByeBug it does throw an error.. which I don't understand.
lib/test.arb:6:in
longest_streak': undefined methodstatus' for [nil, nil, nil, nil, "s"]:Array (NoMethodError) from lib/test.arb:19:in `'
def longest_streak(str)
current = ''
longest = ''
(0...str.length).each do |i|
if str[i] == str[i - 1]
current += str[i]
end
if current >= longest
longest = current
end
end
longest
end
p longest_streak('a') # => 'a'
In Ruby, a negative index will traverse backwards. So str[-1] will go from the end of the array, which will be a since that's the only character in the array.
str[-1] and str[0] are the same thing in this instance, which is why the if condition is evaluated, because i is only ever 0 and 0 - 1 == -1.
You could work around this by adding a check to your conditional
if !(i - 1).negative? && str[i] == str[i - 1]
current += str[i]
end