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liminal_c..

a simple learning array question

in Programming Questions • 2 years ago

I am attempting to get the names of a text string of the objects that are loaded in a two dimensional object array...

so..my beginner question is, can I not call like this on an array?

for (int i = 0; i < cols; i++) {

String rowsarray[] = mods.getSampleName[i];
textout.println(rowsarray[i]);
for (int j = 0; j < rows; j++) {
String columnsarray[] = mods.getSampleName[j];
textout.println(columnsrarray[j]);
}
}

thanks for the guidance

:)

edit:

//maybe this version seems more logical to me, ...but it still doesn't work..my probably equally misguided get method below. I'm sure this is very obviously wrong somewhere...

//

Module[][] mods;

//

for (int i = 0; i < cols; i++) {
String columnarray[] = mods[i].getSampleName;
textout.println(columnarray[i]);
for (int j = 0; j < rows; j++) {
String rowarray[] = mods[j].getSampleName;
textout.println(rowarray[j]);
}
}

//

//class Module method getSampleName

String getSampleName() {
SampleName = s;
return this.SampleName;
}

//another attempt....what is the syntax for this?...ok..i think i'm counting it wrong, but i just want to understand the get syntax..

for (int i = 0; i < cols; i++) {
String columnarray[] = mods[i].getSampleName();
textout.println(columnarray[i]);
for (int j = 0; j < rows; j++) {
String rowarray[] = mods[j].getSampleName();
textout.println(rowarray[j]);
}
}

//String s holds the sample name parameter in the constructor

String getSampleName() {
return this.s;
}

1

Replies(17)

ignivome

ignivome

Re: a simple learning array question

2 years ago

you need to take a look at this : http://www.processing.org/learning/2darray/

your problem is that you're trying to read a SINGLE dimension array
array[] (1 dim) vs array[][] (2 dims)

try something like

for x
for y
print array[x][y];

PhiLho

PhiLho

Re: a simple learning array question

2 years ago

Either you don't show the whole code, or something is missing.
mods[i].getSampleName(); won't work, because getSampleName() is a simple function you defined, not a method of the object store in mods. Unless you omitted the class declaration around this method... It is confusing.
And why are you using a two-dimensional array? We miss a global picture,

liminal_c..

Re: a simple learning array question

2 years ago

yes it is a 2 dimensional array, that is because I am setting up a performance space that has a physical width and depth and it was kind of easier to visualize that space and work with it (I thought) if the virtual space 'looked like' the actual. It's actually supposed to be 3 dimensional eventually...at any rate I realized later that to deal with the data maybe it could have been in a one dimensional array (with a different logic of accessing the objects in it) but this seems like a useful exercise in understanding something anyway and I find it in some ways easier to visualize, so...

sorry i didn't put all the code; i didn't bother because i thought maybe it was so fundamentally obviously flawed somewhere that the first problems could be dealt with first. so i should explain

String getSampleName() {
return this.s;

}

is a method of the class Module (this is more obvious maybe in the middle of the three attempts above)

I want to get the String name of all the audio samples in the 2 dimensional array of Module objects, that name is stored in the object like

//Module class variables

String s;

//constructor

Module(PApplet tp, int tempX, int tempY, int tempW, int tempH, String sample, float temprange) {
//...etc.
s = sample;
}

//a method

String getSampleName(String s) {
return s;
}

I hope that helps to show what I am trying to do - thanks for checking it out

ps - this is so i can print out the names of the samples and check their array postions against what i want the eventual physical distribution in space to be; but i'm pretty sure they are going to be in the wrong order because of the way i've set up the access looping, however the main problem is with correct syntax...i hope....

liminal_c..

Re: a simple learning array question

2 years ago

hmm...well, at least this doesn't report any error..but there's nothing in the generated file..

for (int i = 0; i < cols; i++) {
for (int j = 0; j < rows; j++) {
textout.println(mods[i][j]);
}

}

liminal_c..

Re: Re: a simple learning array question

2 years ago

oh hang on...it does save a text file but the data looks like this

simple_array_trigger16_b$Module@1712651

not like the file name audiosample11.wav (for example)

blindfish

blindfish

Re: Re: a simple learning array question

2 years ago

That output is probably being generated by this line:

textout.println(rowsarray[i]);

...since the content of the rowsarray is another array.

If you're not sure if data is being retrieved and then written to the file, precede the data with a label and run a test. E.g.:

textout.println("sample filename: " + mods[i][j]);

That should at least tell you if this line is actually retrieving anything from the arrays or was just printing a blank line.

Apart from that I'm not sure what to suggest: without a full code listing it's hard to know where you're going wrong. For all we know you're not successfully injecting the data into the array in the first place :/

liminal_c..

Re: a simple learning array question

2 years ago

that almost seems like our posts crossed, or i was editing while you were commenting :) or not - i'm a bit confused right now

anyway, my line was textout.println(mods[i][j]); which did generate the code like text output, one line for each array element, yours adds "sample filename: " to all those - otherwise same....and yes, you're right, its difficult to determine where else i may have screwed up without posting all my code but honestly before i work through some basic knowledge as much as possible i think posting all this code is probably really a forum clutter....on the other hand if you really want to get into that much support...lol

anyway, i really thank you all for helping point me in the right direction as much as possible, it is very helpful

PhiLho

PhiLho

Re: a simple learning array question

2 years ago

"simple_array_trigger16_b$Module@1712651"
In the Module class, you can define a String toString() method which return whatever string you want (can be the name you want, something made of various parts, etc.), making stuff like the println to work.

liminal_c..

Re: a simple learning array question

2 years ago

...been busy with many things, sorry I didn't thank you sooner. :)

and I'm still confused, though maybe minor progress (?) perhaps someone can point out the painfully obvious in this attempt...

/////sketch

int cols = 4;

int rows = 4;
Module[ ][ ] mods; //see Module class
String sample = "audiosample"; //samples on disk are named "audiosample0.wav" etc. (0-15)

PrintWriter textout;

void setup( ) {
size(400, 400);
mods = new Module[cols][rows];
textout = createWriter("samples.txt");
int widthdiv = width / cols;
int heightdiv = height / rows;

for (int i = 0; i < cols; i++) {
for (int j = 0; j < rows; j++) {
mods[i][j] = new Module(i*widthdiv, j*heightdiv, widthdiv, heightdiv, sample + (j + (i * rows)) + ".wav");
}
}

for (int i = 0; i < cols; i++) {
for (int j = 0; j < rows; j++) {
textout.println("sample filename: " + mods[i][j].getSampleName());
}
}
}

/////class 'Module'

class Module {

float x, y;
float w, h;
String s;

Module(int tempX, int tempY, int tempW, int tempH, String sample) {

this.x = tempX;
this.y = tempY;
this.w = tempW;
this.h = tempH;
this.s = sample;
}

String getSampleName() {
return s;
}
}

/////

would appreciate any further guidance. this runs now but there is nothing at all in the samples.txt file that is generated. I am still missing something obvious I feel... and am still not sure if this is the correct way to get those original string names out of the mods array...

PhiLho

PhiLho

Re: a simple learning array question

2 years ago

When using a function, you should read the reference: createWriter()
Don't forget the close(), it is crucial. No need for flush() here (but it doesn't hurt), as close() calls it.

dimiro

Re: a simple learning array question

2 years ago

hi,
is there any online resource besides processing`s webpage and Fry`s book (i think it is very difficult for newbies) to read about 2D arrays?

when you write

for x
for y
print array[x][y];

does this mean that i reads every line & column of the text file as an array?
what is point of writing

int cols = 4;

int rows = 4;

and not writing .length ?

PhiLho

PhiLho

Re: a simple learning array question

2 years ago

1) Probably. Just search for 2D arrays and Java.
2) What text file? print outputs text on the console. Or, in the thread above, textout.println() prints to a text file.
3) No special advantage, except it groups special numbers (dimensions) in a place easy to find, and it is shorter to type...

dimiro

Re: a simple learning array question

2 years ago

thnx for 1 & 3

about 2)
i had in mind something a bit different.say you want to load a text file like this

v1 v2 v3
smthng1 21 24 634
smthng2 765 67 86
smthng3 23 543 456

that has both row & col names that you want to use.
i wrote this

int rows=4;
int cols=4;
void setup(){
size(200,200);
String [] countries=loadStrings("countries.txt");
int [][] values=new int [rows][cols];
new int [][] Countries2=int(split(values,"/t"));
for(int i=0; i<rows; i++) {
for(int j=0; i<cols; i++){
values[rows][cols]=0;
}
}
}
void draw(){
println(countries);
}

and get an error on line 7 no matter how i write it.
i did`t not try it yet with OOP because i am really new at this beacuse the problems that will come up will be even bigger...

is the general approach i am trying here correct?

liminal_c..

Re: a simple learning array question

2 years ago

>Don't forget the close(), it is crucial. No need for flush() here (but it doesn't hurt), as close() calls it.

...and.....it works! :) Actually, the problem wasn't that I didn't read the reference, or use all the related functions (I had flush() and close() in my code I just didn't post that part of the code because it didn't SEEM to be making any difference when I tested it). The reason for that was I placed the println(sample reference) inside the set-up, not in draw. Moving it to the correct place fixed everything. So thanks to you for suggesting i take another look at the way I had set things up.

cheers!

PhiLho

PhiLho

Re: a simple learning array question

2 years ago

@dimiro:
new int [][] Countries2=int(split(values,"/t"));
split returns a one dimension array. You cannot split an array of int, you split strings. The new has nothing to do here. The /t means you split on the sequence / and t. You probably want to split on "\t".
Look in the forum, there are lot of examples of usage of split along with loadStrings.

dimiro

Re: a simple learning array question

2 years ago

phi.lho
ok the \ and / issue is corrected..

i understand what your are saying about "split" it is used for strings, not for arrays..but the problem still remains. :-/

if everything else in the code is correct then how should line 7 be written in order to load the text file in 2d array?

PhiLho

PhiLho

Re: a simple learning array question

2 years ago

Again, search the forum for examples. I haven't said everything else is OK, I corrected the line where you had problems.
You have to loop on the countries array, split each entry to an array, convert the numerical sub-entries to int and assign them to your array entries.
Since you posted on a thread (which isn't your own) which is about learning, I give indications, not code.

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