# Hash Lookup Problem

**URL:** <https://www.ruby-forum.com/t/hash-lookup-problem/151800>\
**Category:** Ruby\
**Created:** [October 25, 2008, 11:59pm UTC](https://www.ruby-forum.com/t/hash-lookup-problem/151800 "2008-10-25T23:59:02Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![paul](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/bbe5ce/32.png) [@paul](https://www.ruby-forum.com/u/paul)\
**Post date:** [October 25, 2008, 11:59pm UTC](https://www.ruby-forum.com/t/hash-lookup-problem/151800/1 "2008-10-25T23:59:02Z")

</div>

I am writing a blackjack simulator. I have classes like Dealer,  
Player, Deck, and Play\_Strategy. Play\_Strategy describes the strategy  
a player will use.  
The strategy basically says what a player should do (hit, stand, etc)  
depending on the cards they are dealt and the dealer’s upcard.

I created a new object for a basic strategy  
(basic.Play\_Strategy.new). Then I have a series of hashes that I have  
set as instance variables instantiated as new hashes (ex. @lookuptable  
= Hash.new).

The idea is that player1 (player1 = Player.new) will look up their  
hand as the key in the basic.action hash. Then it will lookup the  
correct action in another hash based on the dealer.upcard.

Here is the structure of the hashes.

basic.lookup5 = {2 =\> “Hit”,3 =\> “Hit”,4 =\> “Hit”,5 =\> “Hit”,6 =\>  
“Hit”,7 =\> “Hit”,8 =\> “Hit”,9 =\> “Hit”,“T” =\> “Hit”,“A” =\> “Hit”}  
…(removed the full list of arrays to shorten the post)…  
basic.lookupAA = {2 =\> “Split”,3 =\> “Split”,4 =\> “Split”,5 =\> “Split”,  
6 =\> “Split”,7 =\> “Split”,8 =\> “Split”,9 =\> “Split”,“T” =\> “Split”,“A”  
=\> “Split”}

basic.action = {5 =\> basic.lookup5[dealer.upcard],6 =\>  
basic.lookup6[dealer.upcard],7 =\> basic.lookup7[dealer.upcard],8=\>  
basic.lookup8[dealer.upcard],  
9=\> basic.lookup9[dealer.upcard],10=\> basic.lookup10[dealer.upcard],  
11 =\> basic.lookup11[dealer.upcard],12=\>  
basic.lookup12[dealer.upcard],  
13 =\> basic.lookup13[dealer.upcard],14=\>  
basic.lookup14[dealer.upcard],15 =\> basic.lookup15[dealer.upcard],16  
=\> basic.lookup16[dealer.upcard],  
17 =\> basic.lookup17[dealer.upcard], 18 =\>  
basic.lookup18[dealer.upcard], 19 =\> basic.lookup19[dealer.upcard], 20  
=\> basic.lookup20[dealer.upcard],  
21 =\> basic.lookup21[dealer.upcard],“A2” =\>  
basic.lookupA2[dealer.upcard],“A3” =\>  
basic.lookupA3[dealer.upcard],“A4” =\> basic.lookupA4[dealer.upcard],  
“A5”=\> basic.lookupA5[dealer.upcard], “A6”=\>  
basic.lookupA6[dealer.upcard],“A7”=\>  
basic.lookupA7[dealer.upcard],“A8” =\> basic.lookupA8[dealer.upcard],  
“A9”=\> basic.lookupA9[dealer.upcard], “22” =\>  
basic.lookup22[dealer.upcard],“33”=\>  
basic.lookup33[dealer.upcard],“44” =\> basic.lookup44[dealer.upcard],  
“55” =\> basic.lookup55[dealer.upcard], “66” =\>  
basic.lookup66[dealer.upcard],“77” =\>  
basic.lookup77[dealer.upcard],“88” =\> basic.lookup88[dealer.upcard],  
“99” =\> basic.lookup99[dealer.upcard], “TT”=\>  
basic.lookupTT[dealer.upcard], “AA”=\> basic.lookupAA[dealer.upcard]}

Here is what I get…  
puts “Player should #{basic.action[player1.hand.cards]}.” #This is the  
problem! It is as if player.1.hand.cards is an empty array. I get  
“nil”.

I ran some basic testing by seeing if other variables work, and they  
do as follows:

puts player1.hand.inspect # returns an array of two cards. As  
expected.  
puts dealer.hand.inspect # returns an array of two cards. As  
expected.  
dealer.upcard = dealer.hand[-1] #returns a single integer. As  
expected.

puts “Player has #{player1.hand.value}.” # this works too  
puts “Dealer shows #{dealer.upcard}.” #this works too  
puts “Key is #{player1.hand.cards}.” # this works and returns the key  
as expected.

Any ideas why this doesn’t work. When I set this structure up without  
objects it works fine. In other words, instead of basic.action or  
basic.lookup5 I just made them variables not associated with any  
class (ie. basic\_action or basic\_lookup5) and it is ok. It must be  
something with classes I don’t understand.

Thanks for any guidance.

Paul

---

<div class="post-metadata">

**Author:** ![paul](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/bbe5ce/32.png) [@paul](https://www.ruby-forum.com/u/paul)\
**Post date:** [October 26, 2008, 1:48am UTC](https://www.ruby-forum.com/t/hash-lookup-problem/151800/2 "2008-10-26T01:48:28Z")

</div>

On Oct 25, 5:58 pm, Paul [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> 6 =\> “Split”,7 =\> “Split”,8 =\> “Split”,9 =\> “Split”,“T” =\> “Split”,“A”  
> =\> basic.lookup16[dealer.upcard],  
> basic.lookup22[dealer.upcard],“33”=\>  
> “nil”.
> 
> I ran some basic testing by seeing if other variables work, and they  
> do as follows:
> 
> puts player1.hand.inspect # returns an array of two cards. As  
> expected.

If player1.hand is an array, why do you think player1.hand.cards will  
return anything at all?

t