I am not quite sure what I am missing. Thanks for the help in advance!
# Example:
# encoded_string = "m1i1s2i1s2i1p2i1"
# decoded_string = decode(encoded_string)
# decoded_string # => "mississippi"
# decode("f1o2d1")
# "food"
def decode(string)
new_str = ""
i = 0
while i < string.length
letter = string[i]
num = string[i + 1]
num.times {new_str += letter}
i += 2
end
return new_str
end
You've defined a function, but you need to call it or nothing will happen.
As in the example:
decode("f1o2d1")
However there's a bug in your code when you do that.
Consider using string.chars to get the characters and then each_slice(2) to pull out pairs. For example:
string.chars.each_slice(2) do |char, count|
count = count.to_i
# ... Do stuff with this
end
Another trick in Ruby is if you want to repeat a string, multiply it:
'a' + 'b' * 2 + 'a'
# => "abba"
string.chars.each_slice(2) do .... Surely you mean string.each_char.each_slice(2) do ....
each_chars is more efficient. This is an introductory example, mind you, so chars is more self-explanatory.string.chars returns an array. string.chars.each_slice(2) chains the array to the method Enumerable#each_slice, returning an enumerator. An enumerator generates objects. Here those objects are passed to a block. string.each_char.each_slice(2) does the same thing, except string.each_char returns an enumerator, avoiding the creation of the temporary array produced by string.chars, saving memory. The rule is to use chars if it is chained to an instance method of the class Array; use each_char if it is chained to a method that accepts an enumerator as its receiver...each_char rather than chars.The issue is here:
num = string[i + 1]
num.times {new_str += letter}
string[i + 1] returns String—in this case a single character that happens to be a number, like "2". times, however, is a method that belongs to the Integer class. In order to use times on that number, you need to first convert it to an Integer using to_i:
num = string[i + 1].to_i
With that change your code works perfectly: https://repl.it/@jrunning/CriminalGracefulRefactoring
i equals string.length - 1. I suspect that num should be set equal to string[0] in that case.
num.times {new_str += letter}is executed. For example,decode("f1o2d1") #=> NoMethodError (undefined method 'times' for "1":String). That's becausenumis a string, yet the classStringhas no instance methodtimes. Note that this error message pinpoints the problem.