Searching a CSV file - beginner seeking help

ruby-talk
1

Hi all. I've written a little script to search a csv file for films. It
works but has problems. I'd appreciate any pointers with the following:

1. I've used instance variables without a class, to make them visible
amongst methods. Is this acceptable for a short script like this?

2. As it is, it will only match exactly. For example, I have The Mummy
and The Mummy Returns. If I search for 'mummy' program reports "film not
found." I know I need to use Regexp's, not sure how to implement it here
though.

3. Any other comments gratefully received.

···

#################
# search_films.rb
#################

require 'csv'

def load_xvid_file(path_to_csv)
  @names = []
  csv_contents = CSV.read(path_to_csv)
  csv_contents.shift
  csv_contents.each do |row|
    @names << row[0]
  end
  @names.each { |f| f.downcase! }
end

def search_for_film
  print "Enter name of film to search for: "
  film = gets.chomp.downcase
  puts

  if @names.include?(film)
    puts "#{film} found!"
  else
    puts "#{film} not found :("
  end
  prompt
end

def prompt
  print "Search again? (y or n) "
  answer = gets.chomp.downcase

  case answer
  when /y/
    search_for_film
  when /n/
    puts "Goodbye."
    exit
  else
    prompt
  end
end

load_xvid_file("/home/simon/Documents/CSV/XviD.csv")
search_for_film

--
Posted via http://www.ruby-forum.com/.

2

OK
1) I would make this as modular as you can, that way you can expand it when needed.
2) When you do your "if @names.include?(film)" is where you would do your regx search.
Here is a link or so :

3) Working on something for you.

---- Simon Harrison <simon@simonharrison.net> wrote:

···

Hi all. I've written a little script to search a csv file for films. It
works but has problems. I'd appreciate any pointers with the following:

1. I've used instance variables without a class, to make them visible
amongst methods. Is this acceptable for a short script like this?

2. As it is, it will only match exactly. For example, I have The Mummy
and The Mummy Returns. If I search for 'mummy' program reports "film not
found." I know I need to use Regexp's, not sure how to implement it here
though.

3. Any other comments gratefully received.

#################
# search_films.rb
#################

require 'csv'

def load_xvid_file(path_to_csv)
  @names =
  csv_contents = CSV.read(path_to_csv)
  csv_contents.shift
  csv_contents.each do |row|
    @names << row[0]
  end
  @names.each { |f| f.downcase! }
end

def search_for_film
  print "Enter name of film to search for: "
  film = gets.chomp.downcase
  puts

  if @names.include?(film)
    puts "#{film} found!"
  else
    puts "#{film} not found :("
  end
  prompt
end

def prompt
  print "Search again? (y or n) "
  answer = gets.chomp.downcase

  case answer
  when /y/
    search_for_film
  when /n/
    puts "Goodbye."
    exit
  else
    prompt
  end
end

load_xvid_file("/home/simon/Documents/CSV/XviD.csv")
search_for_film

--
Posted via http://www.ruby-forum.com/\.

3

Here you go. This is VERY rough, but it should get you headed in the right direction

···

#################
# search_films.rb
#################

require 'csv'

def load_xvid_file(path_to_csv)
   @names =
   csv_contents = CSV.read(path_to_csv)
   csv_contents.shift
   csv_contents.each do |row|
     @names << row[0]
   end
   @names.each { |f| f.downcase! }
   #puts @names
end

def search_for_film
  @tick = 0
   #puts @names
   print "Enter name of film to search for: "
   $film = gets.chomp.downcase
   puts

   @names.each do |$check|
     puts $check , @tick

     if (/#{$film}(.*)|(.*)#{$film}/i =~ $check)
       @tick = 1
       #puts "TEST"
     end
   end
   if(@tick == 1)
       puts "#{$film} found!"
   else
       puts "#{$film} not found :("
   end
   prompt
end

def prompt
   print "Search again? (y or n) "
   answer = gets.chomp.downcase

   case answer
   when /y/
     search_for_film
   when /n/
     puts "Goodbye."
     exit
   else
     prompt
   end
end

load_xvid_file("movie.csv")
search_for_film

---- Simon Harrison <simon@simonharrison.net> wrote:

Hi all. I've written a little script to search a csv file for films. It
works but has problems. I'd appreciate any pointers with the following:

1. I've used instance variables without a class, to make them visible
amongst methods. Is this acceptable for a short script like this?

2. As it is, it will only match exactly. For example, I have The Mummy
and The Mummy Returns. If I search for 'mummy' program reports "film not
found." I know I need to use Regexp's, not sure how to implement it here
though.

3. Any other comments gratefully received.

#################
# search_films.rb
#################

require 'csv'

def load_xvid_file(path_to_csv)
  @names =
  csv_contents = CSV.read(path_to_csv)
  csv_contents.shift
  csv_contents.each do |row|
    @names << row[0]
  end
  @names.each { |f| f.downcase! }
end

def search_for_film
  print "Enter name of film to search for: "
  film = gets.chomp.downcase
  puts

  if @names.include?(film)
    puts "#{film} found!"
  else
    puts "#{film} not found :("
  end
  prompt
end

def prompt
  print "Search again? (y or n) "
  answer = gets.chomp.downcase

  case answer
  when /y/
    search_for_film
  when /n/
    puts "Goodbye."
    exit
  else
    prompt
  end
end

load_xvid_file("/home/simon/Documents/CSV/XviD.csv")
search_for_film

--
Posted via http://www.ruby-forum.com/\.

4

Sorry, don't know your name. You're just appearing as 'guest'. Are you
sure it's a good idea to have globals in block variables? I've been
continuing to play and the following seems to be what I'm after. Sadly
nothing prints out and the program exits.

def search_for_film
  print "Enter name of film to search for: "
  film = gets.chomp.downcase

  results = @films.grep(/film/)
  if results
    print results
  elsif results.empty?
    puts "Nothing found."
  else
    menu
  end
end

Here is irb demonstrating that it *should* work!

irb(main):009:0> films = ['the mummy', 'the mummy returns', 'the mummy
7', 'the daddy']
=> ["the mummy", "the mummy returns", "the mummy 7", "the daddy"]
irb(main):010:0> films.grep(/mummy/)
=> ["the mummy", "the mummy returns", "the mummy 7"]
irb(main):011:0>

···

--
Posted via http://www.ruby-forum.com/.

5

Got it!

def search_for_film
  print "Enter name of film to search for: "
  film = gets.chomp.downcase

  results = @films.grep(/#{film}/)
  if results
    puts results
    menu
  elsif results.empty?
    puts "Nothing found."
    menu
  else
    menu
  end
end

···

--
Posted via http://www.ruby-forum.com/.

6

This works perfectly for me now. In case anyone may benefit from it:

require 'csv'

def load_xvid_file(path_to_csv)
  @films = []
  csv_contents = CSV.read(path_to_csv)
  csv_contents.shift
  csv_contents.each do |row|
    @films << row[0]
  end
  @films.each { |f| f.downcase! }
end

def search_for_film
  print "Enter name of film to search for: "
  film = gets.chomp.downcase

  results = [@films.grep(/#{film}/)]
  if results
    results.each { |f| puts f }
    prompt
  else
    puts "Nothing found."
    prompt
  end
end

def prompt
  print "Search again? (y or n) "
  answer = gets.chomp.downcase

  case answer
  when /^y/
    search_for_film
  when /^n/
    puts "Goodbye."
    exit
  else
    prompt
  end
end

load_xvid_file("/home/simon/Documents/CSV/XviD.csv")
search_for_film

···

--
Posted via http://www.ruby-forum.com/.

7

Thanks Jesus. I plan to improve script over coming days.

···

--
Posted via http://www.ruby-forum.com/.

8

Thanks marco. Looks like it has potential. I can't think how it would
really help me with this little project but thanks for the link.

···

--
Posted via http://www.ruby-forum.com/.

9

This works perfectly for me now. In case anyone may benefit from it:

require 'csv'

def load_xvid_file(path_to_csv)
@films =
csv_contents = CSV.read(path_to_csv)
csv_contents.shift
csv_contents.each do |row|
@films << row[0]
end
@films.each { |f| f.downcase! }
end

def search_for_film
print "Enter name of film to search for: "
film = gets.chomp.downcase

results = [@films.grep(/#{film}/)]
if results

this will always be true, since you are initializing results to an
array. Enumerable#grep already returns an array, so I'd do:

results = @films.grep(/#{film}/)
if results.empty?
  puts "nothing found"
else
  results.each ...

if results

results.each { |f| puts f }
prompt
else
puts "Nothing found."
prompt
end
end

def prompt
print "Search again? (y or n) "
answer = gets.chomp.downcase

case answer
when /^y/
search_for_film
when /^n/
puts "Goodbye."
exit
else
prompt
end
end

load_xvid_file("/home/simon/Documents/CSV/XviD.csv")
search_for_film

By the way, I'd change a bit around the logic and the user interface,
you seem to have both a little bit mixed up. I would call method
prompt from the main script, in that method I would ask the user for a
word and call search_for_film passing what the user typed. From that
method I would return the results array. Back in the prompt method, I
would print the results and loop for another run. This way,
search_for_film is not tied to the specific user interaction and is
more general and easier to refactor and reuse.

Jesus.

···

On Fri, Apr 1, 2011 at 11:26 PM, Simon Harrison <simon@simonharrison.net> wrote:

10

Hi Simon, just a tip, there is a ruby library to deal with CSV data in
a way very similar to ActiveRecord, but just doesn't work with ruby
1.9.
https://github.com/marcofognog/active_csv

Regards

···

On Apr 2, 4:39 am, Simon Harrison <si...@simonharrison.net> wrote:

Thanks Jesus. I plan to improve script over coming days.

--
Posted viahttp://www.ruby-forum.com/.