CODEWITHSUNDEEP
ruby
Yang Liu
Yang Liu

Reputation: 23

Using Ruby hash key as parameters

I am trying to use a parameter as my key to find the value in a hash, and I just confused about why I couldn't get the value by the first way. I am new to Ruby.

def getCards(player,hash)
    a =$player
    puts "a = "+a.to_s
    puts "a.class = "+a.class.to_s

    puts " hash[:a]"+" #{hash[:a]}"
    puts " hash[:'1']"+" #{hash[:"1"]}"

 end

edit:

 def getCards(player,hash)
   puts player 
  #result successfully 1 or any number that I gets from console

   puts hash[player]
   # nothing but 1 is actually a key in my hash 

# {1=>["yellow3", "yellow8", "green9", "black11", "red1", "black7", "red5", #"yellow7",  more results ..

 end

Upvotes: 2

Views: 565

Answers (1)

tadman
tadman

Reputation: 211540

Note that Ruby is not PHP or Perl, so that should be player and not $player. Argument names and their corresponding use as variables are identical.

$player refers to the global variable of that name, which is unrelated and will be presumed to be undefined unless otherwise set.

Now if by hash[:a] you mean to access the contents of the hash under the key with the player value you've assigned to a then what you actually want is:

hash[player]

Where that represents looking up an entry with that key. a is a variable in this case, :a is the symbol "a" which is just a constant, like a label, which has no relation to the variable.

Don't forget that "#{x}" is equivalent to x.to_s so just use interpolation instead of this awkward "..." + x.to_s concatenation.

Another thing to keep in mind is that in Ruby case has significant meaning. Variable and method names should follow the get_cards style. Classes are ClassName and constants are like CONSTANT_NAME.

Upvotes: 3

Related Questions