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Vectors Versus Arrays

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kbradley

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Vectors Versus Arrays

Sep 26th, 2005

I am designing a Rinex file reader class in Java and this is my first project in Java. I need to store data into an array or vector. I am reading the data from the file related to the time the data occurs. At first I tried to use an array but I do not know the size of the array ahead of time. Is there anyway to make an array change size as it grows in a loop? For example in Matlab you could initialize the array to be an array of zeros. Or do I have to use vectors to do this? I also have this problem with a 3D array that I was creating. How would I use vectors to create a 3D array? Thanks!!

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duckman

Re: Vectors Versus Arrays

Sep 26th, 2005

No, you cannot change the size of an array.
Use an ArrayList instead, not a Vector. Vector has notoriously poor performance, and should only be used when an ArrayList cannot provide the functionality needed while a Vector can (by the time you know when that is you know what it is).

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Narue

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Re: Vectors Versus Arrays

Sep 26th, 2005

Vectors are evil, look up the ArrayList if you want an array that grows as needed.

I'm here to prove you wrong.

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kbradley

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Re: Vectors Versus Arrays

Sep 26th, 2005

Thanks for your help. I have tried looking up arraylist on the Java Api site but I am having a little trouble understanding what it is and what syntax is required to make it work. Can anyone give me a better explanation than what is on Sun's page? Thanks!!

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Re: Vectors Versus Arrays

Sep 26th, 2005

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
import java.util.*;
 
class Test
{
     public static void main(String[] args)
     {
            ArrayList al = new ArrayList();
            al.add("one");
            al.add("two");
      }
}
import java.util.*;

class Test
{
     public static void main(String[] args)
     {
            ArrayList al = new ArrayList();
            al.add("one");
            al.add("two");
      }
}

Notice how there's no set size anywhere.

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duckman

Re: Vectors Versus Arrays

Sep 27th, 2005

How can someone understand Vector but not ArrayList?
They have the exact same interface...

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Re: Vectors Versus Arrays

Sep 27th, 2005

Hi everyone,

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Originally Posted by Narue

Vectors are evil, look up the ArrayList if you want an array that grows as needed.

Narue what makes you say that vectors are evil?

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duckman

Re: Vectors Versus Arrays

Sep 27th, 2005

The same reason I say they should be deprecated (or better yet, banned to the 7th circle of computer hell)

They're slow, have a confusing API (with many duplicate functions) because of the way they were retrofitted to support the List interface, are generally not needed (and when you could have a case for them there are still better alternatives), etc. etc.

Basically they're among the dinosaurs of Java, together with StringTokenizer and some other very old classes that now have better alternatives but have been kept on because someone forgot to remove them.

As people are clearly allowed to attack me but I'm not allowed to defend myself, I no longer post to this site.