referring to object variables in array

Programming Questions

.IT.

referring to object variables in array

in Programming Questions • 3 years ago

Hi, hello

I've been trying various ways to structure this, but I always end up stuck.

What I'm trying to make is a conjugational table for verbs where the user has to write in the conjugations and have feedback of whether it was correct.

My problem for now is grouping that mass of variables for the many conjugations of a verb (where of course I'd have tons of verbs later, of which it needs to pick a random one).

My first approach was making a verb class, but then the objects deriving from it would have to look like -

Verbs verb1 = new Verb (conj1, conj2, 3, 4, 5, 6......30);

Verbs verb2 = new Verb (conj1, conj2, 3, 4, 5, 6......30);

.... verb117 ...verb129 ...

which I thought was impractical. Then I created the individual verbs as classes making their own object. I still don't think that's optimal.

>>What is annoying me most though, is that I can't figure out how to refer to the variables (properties) of the objects to then check them against the user input. I also figure all the objects have to be in an array so that I can later tell it to pick one at random, display it and ask for its conjugations. (I'll use controlP5 text boxes for the user input).

The need for them to be in an array then makes it so that I'd have to refer to the picked verb as > verbList[randNum]

and I can't refer to it with > verb1.conjugation5 (for example)

Can you help me structure and express that to make it work ?

Replies(6)

PhiLho

Re: referring to object variables in array

3 years ago

" Verbs verb1 = new Verb ( " Should be Verb verb = new Verb(
" .... verb117 ...verb129 ... " Indeed an array is in order, and you should put the data in a file (eg. a CSV text file) to populate the array, instead of putting the data in the code itself.
" I can't figure out how to refer to the variables (properties) of the objects to then check them against the user input "
Perhaps you should read (again?) Objects article.
" I'd have to refer to the picked verb as > verbList[randNum]and I can't refer to it with > verb1.conjugation5 "
verbList[randRum].conjugation5 should work.
Or Verb verb = verbList[randRum]; then use verb.conjugation5

.IT.

Re: referring to object variables in array

3 years ago

Hi, thanks for the reply ~

I've read it tons of times yeah... hmm the verbList[randNum].conj1 didn't work. What i'm getting is the .var referring to the type of the array somehow =S

I don't know if it's correct but after much trial and error i made the array type as Object verbList ..etc.

println(verbList[1]);

prints >>> word_test$to_be@173ec72 (that is file_name$verb@173ec72) (those last numbers after the @ i noticed are random with every run)

Another thing, in a similar file>

I did make the verbs in .txt files. Having it load the lines in an array with loadStrings();

That worked well until i realized the array it creates is local, and i can't refer to it from other places.

What would be a way to make that array global?

With picking a random verb from a list, i wouldn't know how to tell it then to load that exact file of the verb. =S

PhiLho

Re: referring to object variables in array

3 years ago

" the verbList[randNum].conj1 didn't work. What i'm getting is the .var referring to the type of the array somehow"
Yes, that's the idea!
" i made the array type as Object verbList"

" println(verbList[1]); prints >>> word_test$to_be@173ec72"

Indeed, word_test is the name of the main class (the sketch's name, the class is generated by Processing); to_be is the name of an inner class of the main class and the number is actually the reference of the object's instance.
So, if I interpret this correctly, you have created one class per verb! (supposing you have the classes to_eat or to_run, etc.).
If so, I understand better the first sentence I quoted...
If that's the case, this approach isn't the right one. You should make a couple of classes, the most generic possible.
Possibly a generic class for regular verbs, a sub-class for irregular ones, etc. Or just one class with the right flags/data.

At this step, I suggest to show your code. If too long, show it in a pastebin site (eg. pastebin.com or pastebin.ca). Maybe it is short if you just show the main code and one of your classes!

" the array it creates is local, and i can't refer to it from other places.What would be a way to make that array global?"
Mmm, that's Processing 101. Are you trying to run (using classes) before knowing to how to walk?

I don't blame you (see no offense here!), just wondering. Actually nothing wrong here, you took the right side of the problem, but that's more to learn.

Or perhaps I am just mis-understanding your question. Well, let's make the base answer, correct me if the problem is deeper: to make a variable (be it integer, array or object) global, you declare it outside (usually, before) setup() and other functions.

.IT.

Re: referring to object variables in array

3 years ago

Haha, true i haven't done this before but i find it a great way to learn when i have a goal and keep trying different ways. I also don't think it's that complicated. But unexpected things turn up that i can't figue out.

I always read the processing help, but it doesn't mention specific things like those.

I know about declaring things outside setup() to make it global. The thing is that even if i do, it later says it can't find that array when i refer to it. Like this >

String wordList [] = loadStrings("theTextFile.txt");
void setup(){
for (int i=0; i<wordList.length; i++){
println(wordList[i]);
}
}
void draw(){
}

When I run it says - NullPointerException. Later i put that loadStrings in the function of a controlP5 button, and i could refer to it just fine. It seemed to work as long as the load code was close to the code referring to it later.

void setup(){
String wordList [] = loadStrings("theTextFile.txt");
for (int i=0; i<wordList.length; i++){
println(wordList[i]);
}
}
void draw(){
}
void mousePressed(){
if (mouseButton== LEFT) {
println(wordList[1]);
}
}

IF i do put it in the setup(), it works and prints. But then when i refer to it from outside it says - cannot find anything named wordList. I think arrays created in setup() should still be accessible anyway. So i concluded this one is local somehow.

About the classes problem. If i make a generic class (say Verbs) i only need one, so that i can keep it simple, i don't need separate for regular/irregular. And if i have one generic, then what ? =s Make the different verbs from it ? I had something like that at first (first post).

blindfish

Re: referring to object variables in array

3 years ago

I haven't read the full thread here, so apologies in advance if I'm stating the obvious.

You should be able to declare a variable before setup, to make it global, and then set its value within setup (untested):

// declare
String wordList[];
void setup(){
// populate the variable
wordList = loadStrings("theTextFile.txt");
for (int i=0; i<wordList.length; i++){
println(wordList[i]);
}
}
void draw(){
}
void mousePressed(){
if (mouseButton== LEFT) {
println(wordList[1]);
}
}

IIRC the problem with loadStrings() is that, by default, it loads from the data folder and the location of this is established when setup runs and not before; hence the need for the above 'workaround'...

.IT.

Re: referring to object variables in array

3 years ago

Hi hi, thanks for the attention.

To blindfish - I was just going to write how this didn't work as well when i tested yesterday, but i just re-tested and it did work :O

String wordList[]; - thanks for that too! I've been struggling with declaring an array without specifying its length or content >.>

The only suggestions in the processing help didn't have that and i thought i couldn't do it that way.

The objects though i still can't figure out. I'll keep trying and paste some code later~

Top Reply