Ruby程序返回错误“将字符串隐式转换为Integer（TypeError）”

Question

I'm trying to create a replica of Go Fish to help me learn more about arrays and hashes, and just how to go about structuring data. I'm on day two and have what looks to be much closer to the end goal. Keep in mind, I'm new to this. Anyway, here's the problem I'm running into:

=> gofish.rb:21:in `player_turn': no implicit conversion of String into Integer (TypeError)

I understand why I'm getting the error, but I can't figure out how to use the .shift method without giving an index number. I would like to select which object to shift based on the value instead. So, if I correctly guess do you have an 'ace of spades', the card is removed from the cpu_hand array and is added to the my_hand array. With that said, I would just like to know the best way to go about this.

Here's my script:

card_values = ['ace', 'two', 'three', 'four', 'five', 'six', 'seven',
 'eight', 'nine', 'ten', 'jack', 'queen', 'king']
suits = ['spades', 'diamonds', 'hearts', 'clubs']

# creates array objects with every value and suit possible (full deck)
card_deck = card_values.product(suits).collect{|card, suit| "#{card} of #{suit}"}

def print_hand
  puts "Your hand: #{@my_hand.join(', ')}."
end

def player_turn
  puts "You go first!"
  puts "Do you have a..."
  puts @cpu_hand.join(', ')
  print "> "
  @card = $stdin.gets.chomp.downcase
  # if cpu has the card requested give it to the player and add to their array
    if @cpu_hand.include?(@card)
      puts "Ahhh...you got me. Here you go!"
      @my_hand.shift(@cpu_hand[@card]) # ****Here's the error(line:21) 
      print_hand
    else
      puts "Go fish!"
      @my_hand.shift(@card_deck[1])
      print_hand
    end
end


puts "There are #{card_deck.length} cards in this deck."
puts "Welcome to Go-Fish."
print "Your name please: "
player_name = $stdin.gets.chomp.capitalize

puts "Ok #{player_name}, lets get this deck shuffled..."
#sleep(1)
# shuffles card_deck using .shuffle method
card_deck = card_deck.shuffle
puts "Cards are perfectly shuffled!"
#sleep(1)
puts "Dealing cards..."
#sleep(1)
# assigns first 7 cards to user, removes from card_deck
@my_hand = Array.new
@my_hand = card_deck.shift(7)
# assigns next 7 cards to CPU, removes from card_deck
@cpu_hand = Array.new
@cpu_hand = card_deck.shift(7)

print_hand

until card_deck.length < 1 || @cpu_hand.length < 1 || @my_hand.length < 1
  player_turn
end

puts "GAME OVER!"

Answer 1

In your error line,

@my_hand.shift(@cpu_hand[@card])

your crash is caused by attempting to index into the @cpu_hand array with a string ( @card ). The second issue is trying to call shift using a string as a parameter. Both of these need to be integers. shift removes the first element (or first n elements if an integer parameter is specified); this seems appropriate for taking an item from card_deck , but you'd want push , unshift , or << to add an element to @my_hand . You'll also need a method to remove the specified card from @cpu_hand , delete :

if @cpu_hand.include?(@card)
  puts "Ahhh...you got me. Here you go!"
  @my_hand << @cpu_hand.delete(@card) # transfer a card from CPU to my hand
  print_hand
else
  puts "Go fish!"
  @my_hand << card_deck.shift # take the first card from the deck (could also be pop?)
  print_hand
end

However, card_deck is not a global like your other variables, so you'll need to pass it into the function and change the function header to def player_turn card_deck , or make it global. But making everything global is generally considered poor design because data can be mutated from anywhere, leading to difficult-to-find bugs. Consider writing classes such as Hand and GoFish (for example) that encapsulate all of the logic necessary to represent reusable pieces of your game.

I recommend taking a read through the array docs . You'll surely find some cool methods and learn a few tidbits.