"If equal to a letter"

Question

I am trying to write a method that takes in a string that will have no spaces. All I want it to do is to return "bug" when the character in the string is a letter [A-Za-z] and to return "ant" if it's any other character.

def Letter(str)
    (0..str.length).to_a do |index|
        if str[index].chr =~ /[A-Za-z]/ ##I think this is where things are going wrong.
            puts "bug"
        else
            puts "ant"
        end
    end
end

Does anyone have any idea how to fix this? I keep getting arrays of consecutive numbers.

`=~` [is the correct operator to compare against a regex](http://stackoverflow.com/questions/5781362/ruby-operator), not the `=` assignment operator. — Michael Berkowski, Sep 11 '14 at 01:11
Still getting an array of numbers, but thanks for the correction! — theamateurdataanalyst, Sep 11 '14 at 01:14
To make your code work, you need to replace (1) `to_a` with `each` (2) `(0..str.length)` with either `(0..str.length-1)` or `(0...str.length)` (three dots) and (3) `str[index].chr` with `str[index]`. (2) is because, if `str = "cat"`, `(0..str.length) => (0..3)`, and when `index` gets to `3`, `str[3] => nil`, causing `"ant"` to be printed at the end, when it shouldn't be. @Amadan shows you the Ruby way to approach this problem. He also suggests some coding conventions to follow. I'll add one more: indent two spaces. — Cary Swoveland, Sep 11 '14 at 03:28
@the Tin Man Not homework. Just self practice. Plus I showed all my steps so let me know if I am not using proper etiquette and I will make sure to improve my question next time. — theamateurdataanalyst, Sep 11 '14 at 03:41

score 3 · Accepted Answer · answered Sep 11 '14 at 01:17

Rewritten

def letter(str)
  str.each_char.map do |char|
    (char =~ /[[:alpha:]]/) ? 'bug' : 'ant'
  end
end

In your code, you are trying to print "bug" or "ant"; but you're returning (0..str.length).to_a. This function will return an array of bugs and ants. It is also made more Rubyish:

methods should be in snake_case (lowercase, with underscores between words)
iterating over strings is easier with each_char
it's fine with [A-Za-z], but [[:alpha:]] is both clearer and handles Unicode stuff.
since we're testing each character, you know it's going to be one character long, so you don't need the start of line and end of line anchors.

Schylar · Answer 2 · 2014-09-11T18:09:56.063

-1

def letter(str)
    str.chars.each do |x|
        puts x=~ /[A-Za-z]/ ? "bug" : "ant"
    end
end

First things first, in your loop your are trying to convert a range into an array.

(0..str.length).to_a

str.length returns a number, therefore making it into an array will give you an array of numbers. Hence your problem.

Second, you have to have brackets around your /a-zA-Z/ regex
Third, use the ternary operator. It's great for small if statements. Heres the syntax:

boolean ? "if boolean is true this code will execute" : "else this code will"
Fourth, use the .each methods, ruby is loved partly because of the simplicity of loops and iterating!

Happy coding!

edited Sep 11 '14 at 18:09

answered Sep 11 '14 at 01:32

Schylar

774
1
5
13

This won't work. `return` will immediately exit the method as soon as the ternary statement returns its value in the first iteration. `each` isn't going to iterate over the values of `str.chars` and *return* an array of "bug" and "ant" variables, it only iterates. – the Tin Man Sep 11 '14 at 02:46
I was unsure if he wanted to only output "bug" once or for each iteration that matched the regex. My fault, I fixed the code accordingly. – Schylar Sep 11 '14 at 03:50
No, that still won't work. `each` won't return what you think it will. Run your code in IRB and look at what's returned by the method. – the Tin Man Sep 11 '14 at 17:13
You are correct, @theTinMan, however `.each` yields exactly what I think it will. I forgot to print it out over each iteration. Thanks! – Schylar Sep 11 '14 at 18:19
Well, be careful with not answering the OP's question. The requirement is a method that *returns* the values. – the Tin Man Sep 11 '14 at 22:54

"If equal to a letter"

2 Answers2