Weird thing about hashes and keys?

[Milena]

I came across a weird thing about hashes.

here's my code:

module RPGMakerWeb Message_If_Actor = { 1 => "Attack", 128 => "Attack 128!" }endclass Window_BattleLog < Window_Selectable #-------------------------------------------------------------------------- # * Display Skill/Item Use #-------------------------------------------------------------------------- def display_use_item(subject, item) if item.is_a?(RPG::Skill) add_text(subject.name + RPGMakerWeb.values[item.id]) unless item.message2.empty? wait add_text(item.message2) end else add_text(sprintf(Vocab::UseItem, subject.name, item.name)) end endendso apparently, I want the subject to say for example: "Eric: Attack 128"! if I use skill 128. As you can see on my hash I have 128 key. But whenever I execute the script, somehow the hash doesn't recognize 128 as a key and so it won't display the value of key 128. It says can't convert String to nil.

Also, if possible, is there a way to make the subject talk different words depending on if they're actors or not?

 

[Shaz]

There's no such thing as RPGMakerWeb.values - you created RPGMakerWeb.message_if_actor which HAS a property called values.

add_text(subject.name + RPGMakerWeb::message_if_actor[item.id])

 

[Milena]

There's no such thing as RPGMakerWeb.values - you created RPGMakerWeb.message_if_actor which HAS a property called values.

add_text(subject.name + RPGMakerWeb.message_if_actor[item.id])or it might be RPGMakerWeb::message_if_actor[item.id]

Oh wait, I see. Let me check this out. 

Edit: This doesn't work. Still getting the nil error.

If I put in 2 as thet values it works, but when I use skill 128 which is the key I wanted, well it doesn't.

 

[Zalerinian]

Please show a screenshot of the error. According to your first post, there is no value for 2.

 

[nio kasgami]

simply you also need to input the to_s because this need to be convert into string 

but I think you have two proble ...but not sure but you have to do this 

def display_use_item(subject, item) @value = RPGMakerWeb::Message_If_Actor[item_id] if item.is_a?(RPG::Skill) add_text(subject.name + @value.to_s) unless item.message2.empty? wait add_text(item.message2) end else add_text(sprintf(Vocab::UseItem, subject.name, item.name)) end endendthe to_s allow to value to be  convert into string and don't call module instance directly in the method like that put it into a Global like ( @value ) it is better for comprension and advoid ridiculous bugs

 

[BoluBolu]

@nio_kasgami
 

simply you also need to input the to_s because this need to be convert into string

This is not nedeed.
RPGMakerWeb::Message_If_Actor[128] should give the value of this : "Attack 128!"  <= which is already a string.
I mean the values inside the has is already string.
I believe the problem might be this RPGMakerWeb::message_if_actor[item.id] the message_if_actor is all in lowercase?  it should be Message_If_Actor
You need to give more info
 

 

[FenixFyreX]

@Shaz - Woah, not sure if you were confused as to whether the OP was using a method or not...your message_if_actor is lowercase, not a constant like the OP has in their code, so your explanation is error-prone and as the OP suggested, didn't work.

@OP - When we look at a hash, it is technically made up of two arrays: keys, and values. Each object in keys refers to the same-indexed value in the values array.

Now, in Ruby 1.9 and up, hashes are ordered; that is, when you create a key/value pair and add it to a hash, then it is the nth pair in the hash. Let's look at this hash:

module RPGMakerWeb  Message_If_Actor = {    1 => "Attack",    128 => "Atack 128!"  }end How do we access this hash? Well, it's a constant in the module RPGMakerWeb, so to access it, would look something like:

RPGMakerWeb::Message_If_Actor Now. When we use the #keys and #values methods of Hash, it returns separate arrays. We have added 1 => "Attack", then 128 => "Attack 128!", so the key and value arrays would look something like:

RPGMakerWeb::Message_If_Actor.keys   #=>   [1, 128]RPGMakerWeb::Message_If_Actor.values   #=> ["Attack", "Attack 128!"] So, we see that "Attack 128!" is index 1 of the values array. You have tried to do this:

RPGMakerWeb.values[128] There are two things wrong with this code; first of all, RPGMakerWeb is not the hash; it's the container module in which the hash is stored, so we change that to

RPGMakerWeb::Message_If_Actor.values[128] ..But it still errors! Ah, the reason for that is simple. When you call #values on the hash, it returns an array, not the hash itself! Therefore, the index you need to use is 1. This is why you need to leave out '.values', and do this instead:

RPGMakerWeb::Message_If_Actor[128] That is the correct code; see, when you access a hash, the value inbetween the []s is the 'key', and what is returned is the 'value'.

Hope this explanation helped

 

[Shaz]

which is pretty much what I had, without the lower case typo (sorry about that - I am way more familiar with calling methods than constants) ... and a much more interesting and helpful explanation


However, what happens if the hash doesn't contain the key? It's honestly too early in the morning for me to work through it, but does there need to be a .has_key? test in there somewhere, or a default value stored with the hash to return in case of no key?

 

[Another Fen]

Did you get that error message when using
RPGMakerWeb.values

or

RPGMakerWeb::message_if_actor

?

As it was already stated above, none of these calls should work because the respective methods should not exist for a Module object, so I would have expected a corresponding error message (however, I don't know your entire scriptset of course and I might overlook something). Are you sure this line caused the error?

When you are sure you used the right call but are still getting funny results, consider to do a console output of all elements involved to check if they have correct values, for example

p RPGMakerWeb::Message_If_Actor, item.id
 

When you test a script using the Battle-Test-Mode from the database, be sure to save your project before you do. Otherwise the game won't use the latest scripts (you won't have to save when you just edited items in the database).

You can test if a battler is an actor by using either its actor? or enemy? method.

 

[FenixFyreX]

@Shaz, that's where even the final code I posted would fall through; there should be a conditional if statement that checks whether the key is there or not, and only if there is, add the text. So,

my_value = RPGMakerWeb::Message_If_Actor[item.id]add_text("#{subject.name}#{my_value}" if my_value#...rest of the method

If we were to get down into details, the OP should alias the method, not overwrite it, and a few other things need to happen before the code is completely clean; however, they are learning! So these such things aren't expected to come instantly.

 

[Shaz]

I was just thinking it might throw an error or give unwanted results if the key wasn't there, which would prompt another request for help

 

[Milena]

Thanks for replying and for all the solutions. Normally, I wanted the item.id (which would be the id of the skill I just used) to be the ones given or thrown out as the value inside the hash. Here's my full code I tried:

module Heartfire module Message Actor_Quotes = { 128 => "Attack #128!" } endendclass Window_BattleLog < Window_Selectable #-------------------------------------------------------------------------- # * Display Skill/Item Use #-------------------------------------------------------------------------- def display_use_item(subject, item) if item.is_a?(RPG::Skill) if subject.is_a?(Game_Enemy) add_text(subject.name + Heartfire::Message::Actor_Quotes[item.id]) add_text(subject.name + item.message1) end unless item.message2.empty? wait add_text(item.message2) end else add_text(sprintf(Vocab::UseItem, subject.name, item.name)) end endendThe scenario is like this. I made a skill called Forbidden Attack, which is under 128th skill of the Skills Database. Now, whenever I use that skill, I wanted it to throw another line of quote when the actor uses it. I tried doing it without the .values and here's what happens:

So I was thinking what could have been wrong with it. 

If I used Skill #128, shouldn't this code:

add_text(subject.name + Heartfire::Message::Actor_Quotes[item.id])throw out the 128th key or numbered key's value on the Hash?

 

[Shaz]

That's where you have to add the check to ensure it's in the hash:


http://forums.rpgmakerweb.com/index.php?/topic/31616-weird-thing-about-hashes-and-keys/#entry307772

 

[Milena]

Thanks, now solved! Requesting the thread to be closed.

 

[Shaz]

This thread is being closed, due to being solved. If for some reason you would like this thread re-opened, please report this post and leave a message why. Thank you.