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Index › Programming Questions & Help › Syntax Questions › how to randomize an array of strings

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how to randomize an array of strings (Read 1075 times)

markallen3 YaBB Newbies Offline Posts: 2	how to randomize an array of strings Nov 9^th, 2006, 5:53pm Is there an easy way to randomize an array of strings? I tried myStringArray.randomizeArray();

JohnG

Re: how to randomize an array of strings
Reply #1 - Nov 9^th, 2006, 6:39pm

It's not too hard to randomise the array, but you have to do it manually.

This is one way, it's not very efficient, but easy to see how it works (and will be fine with reasonable sized arrays)

It may also have bugs as I don't have time to check it at the moment, but it at least shows a machanism for doing what you need.

Code:

String[] myText;
// fill myText however you need...

String[] randText=new String[0];
int num=myText.length;
for(int i=0;i<num;i++)
{
  int id=(int)random(0,myText.length); 
  //pick an element of myText at random;

  randText=append(randText,myText[i]);
  //add it onto the end of randText;

  //now we need to remove that element from myText
  if(id==0) //special case #1
    myText=subset(myText,1,myText.length);
  else if(id==myText.length-1) //special case #2
    myText=contract(myText,myText.length-1);
  else // general case
  {
    String[] start=subset(myText,0,id);
    String[] end=subset(myText,id+1,myText.length);
    myText=concat(start,end);
  }
}

st33d

Re: how to randomize an array of strings
Reply #2 - Nov 9^th, 2006, 6:56pm

The easiest method is to use an ArrayList. It's like an normal array but it's an object version (I know arrays are objects but we generally consider them apart from objects and primitives).
Code:


ArrayList blah;

void setup(){
  // An ArrayList is an object version of an array - more powerful
  blah = new ArrayList();
  // Our Strings have to wrapped in an object
  // A StringBuffer is the standard object wrapper for Strings
  // Use it when you manipulate Strings - it's fast and will save you memory
  blah.add(new StringBuffer("bob"));
  blah.add(new StringBuffer("dave"));
  blah.add(new StringBuffer("charly"));
  blah.add(new StringBuffer("joe"));
  
}

void draw(){}

void mousePressed(){
  // Now you've used an ArrayList you can use Collections for a little magic...
  Collections.shuffle(blah);
  for(int i = 0; i < blah.size(); i++){
    StringBuffer temp = (StringBuffer)blah.get(i);
    println(temp.toString());
  }
  println();
}

Java documentation on ArrayList

Java documentation on Collections

Edit:

Oops - simultaneous post! Not trying to upstage you John, just took a while to read the reference docs.

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