Str.Each in Ruby Isn't Working

Why join won't work in this each statement

The key here is you're trying to modify i while inside an each block, but as i is a local variable, it has no effect on the original.

What you want is:

arr2.collect! do |i|
  i[0].upcase!
  i.join
end

This rewrites the contents of the array.

What you can do, though, is roll this up into a simple gsub:

def capitalize(string)
  string.gsub(/\b([a-z])\B/) do |m|
    $1.upcase
  end
end

iterating over each character of a String in ruby 1.8.6 (each_char)

I have the same problem. I usually resort to String#split:

"ABCDEFG".split("").each do |i|
  puts i
end

I guess you could also implement it yourself like this:

class String
  def each_char
    self.split("").each { |i| yield i }
  end
end

Edit: yet another alternative is String#each_byte, available in Ruby 1.8.6, which returns the ASCII value of each char in an ASCII string:

"ABCDEFG".each_byte do |i|
  puts i.chr # Fixnum#chr converts any number to the ASCII char it represents
end

Why doesn't each_slice work?

In ruby 1.8.6 you have to require 'enumerator' (which is part of stdlib and has been merged into core in 1.8.7+) before using each_slice.

Sadly the ruby-doc lists methods that are added to core classes by stdlib without mentioning where the methods are from.

How to iterate through array of strings from database Ruby on Rails

If you're saving an "exact" array as a String, then Array#each won't work, because isn't a method in the String class.

Maybe isn't the best option, but you could use JSON.parse and this way get your array and be able to iterate over each object inside:

require 'json'

str = '["item1", "item2", "item3"]'
JSON.parse(str).each { |item| p item }
# "item1"
# "item2"
# "item3"

In order this work your string must be an array, in your example the second item is missing its double quote.

You could consider working with serialization or array data types depending on you current database.

Ruby Loops not working properly

This isn't sane:

check_box_tag(x[i], checked_value = 1, unchecked_value = 0)

The method definition is:

check_box_tag(name, value = "1", checked = false, options = {})

You're passing 1 for value, and 0 for checked. You cannot "name" parameters with variable = value, all you're doing is setting a variable and then passing the same value through to the method.

If you want to produce a checkbox where the name is the sport's name and its value is the id of the sport, get rid of your pair of loops and just us a single loop:

def sport_select(sport)
  Sport.all.map do |e|
    check_box_tag(e.sport_name, e.id)
  end
end

If you're outputting the result to a page, you will also probably want to use .join('').html_safe to return a single string, and prevent it from being escaped.

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