Bringing values into a loop in Ruby - ruby-on-rails

Question

This is almost certainly a duplicate, but I can't find the original - I don't know the search terms to use. Which is why I'm on Stackoverflow instead of Google :)
Anyhow, here's my code:
def titleize(say)
index = 0
words = say.split
words.each do |word|
unless word == "and" || "or" || "over" || "the" || "for"
word.capitalize!
end
if index == 0
word.capitalize!
end
index += 1
end
say = words.join(" ")
end
Because index is declared before the loop, my if index == 0 is not working.
How do I let Ruby know about and use my object index? Also: what is this called?

Answer 1

Using index == 0 is perfectly fine as index is accessible within your loop. Your real problem is probably in this line:
word == "and" || "or" || "over" || "the" || "for"
This is always true-like! What you mean is:
["and", "or", "over", "the", "for"].include? word
Apart form that there is a method called each_with_index, which you can use like this:
words.each_with_index do |word, index|

Answer 2

I think you want to use with_index. Your word comparison was busted too.
def titleize(say)
words = say.split
l = ["and", "or", "over", "the", "for"]
words.each.with_index do |word, index|
word.capitalize! if index == 0 || !(l.include? word)
end
say = words.join(" ")
end
puts(titleize("hello there for you"))
puts(titleize("hi"))
puts(titleize("for"))

Answer 3

That's not how booleans work. The way this is evaluated is:
x == 'a' || 'b'
Becomes:
(x == 'a') || 'b'
Which is equivalent to:
'b'
What you're intending, translated to more idiomatic Ruby, is:
def titleize(say)
say.split.each_with_index do |word, index|
if (index == 0)
word.capitalize!
else
case (word)
when "a", "and", "or", "over", "the", "for"
# Leave lower-case
else
word.capitalize!
end
end
end.join(' ')
end
titleize('the time this is a test for the things!')
# => "The Time This Is a Test for the Things!"

Answer 4

I would do this it is more flexible and more ruby-esque
def titleize(sentence,exclusions=[])
sentence.split.map.with_index do |word,index|
(index == 0 || !exclusions.include?(word)) ? word.capitalize : word
end.join(' ')
end
For this case i used 'capitalize' without the bang in case any of the words are already capitalized.
"Hello".capitalize! #=> nil
"Hello".capitalize #=> "Hello"
It will also let you re-use the same list of exclusion or change them as you see fit
Call as
exclude = ["and", "or", "over", "the", "for"]
titleize("hello there you are over there", exclude)
#=> "Hello There You Are over There"

Answer 5

Your code returns the modification of say, but does change the contents of the variable. It appears that you want to modify the argument, but I'm not sure about that. I will first suggest a way to return the modified value of say (but not alter the value of say, and then will show how you could change the code to modify the argument.
Notice that I do not employ an index, and use a case statement to determine whether words after the first should be capitalized.
Code
def titleize(say)
words = say.split
return "" if words.empty?
words.first.capitalize!
return words.first if words.size == 1
words[1..-1].each do |word|
case word
when "and", "or", "over", "the", "for"
else
word.capitalize!
end
end
words.join(' ')
end
Examples
say = "and now is the time for all Rubyists to hunker down and code"
titleize(say)
#=> "And Now Is the Time for All Rubyists To Hunker Down and Code"
say
#=> "and now is the time for all Rubyists to hunker down and code"
say = " "
titleize(say)
#=> ""
say = " and "
titleize(say)
#=> "And"
Modifying the Argument
If you wish to modify the argument say, use String#replace:
def titleize_and_modify_arg(say)
words = say.split
str =
case words.size
when 0
""
when 1
words.first.capitalize
else
words.first.capitalize!
words[1..-1].each do |word|
case word
when "and", "or", "over", "the", "for"
else
word.capitalize!
end
end
words.join(' ')
end
say.replace(str)
end
say = "and now is the time for all Rubyists to hunker down and code"
titleize_and_modify_arg(say)
#=> "And Now Is the Time for All Rubyists To Hunker Down and Code"
say
#=> "And Now Is the Time for All Rubyists To Hunker Down and Code"
say = " and "
titleize_and_modify_arg(say)
#=> nil
say
#=> " and "
Notice that in the second example, titleize_and_modify_arg modifies say correctly, but returns nil. Of course, the method could be easily changed to return the value of say, as well as changing it, if that were desired.
Note also that, in the case statement, when words.siz => 1, it's capitalize, not capitalize!, as the latter would return nil if the word is already capitalized. capitalize! is need for the else case, however.

Answer 6

I recommend using each_index instead of each. See here.
Try this:
def titleize (say)
words = say.split
words.each_index do |index|
word = words[i]
unless word == "and" || "or" || "over" || "the" || "for"
word.capitalize!
end
if index == 0
word.capitalize!
end
end
say = words.join(" ")
end