Hashtable help- using strings

Question

I want to take a String str and an int wSize and use it to create a hashtable. An example is the best way to explain what I want.

For example: str = "alphabet" wSize = 2

I want a hashtable that looks like this: al 0 lp 1 ph 2 ha 3 ab 4 be 5 et 6

This is what I have so far

public static void hashTableCreator (String str, int wSize) {
    Hashtable ht = new Hashtable();
    str = "alphabet";
    wSize = 2;
    String str2;

    for (int i = 0; i < str.length(); i++) {
      int value = 0;
      ht.put(str.substring(i, i + 1), value);
      value++;
    }

    Set set = ht.keySet(); 

    Iterator itr = set.iterator();
    while(itr.hasNext()) {
      str2 = (String) itr.next();
      System.out.println(str2 + ": " +
                         ht.get(str2));
    }

  }

I don't understand, you have parameters in your method, but you're setting values to them on the next line. Whats the point of the parameters? — Austin
– Austin, Commented Sep 22, 2012 at 22:00
The question is how would i go about implementing the thing I want. And the parameters are for later use, this is just an example I want to test. — ellangog
– ellangog, Commented Sep 22, 2012 at 22:05
You implemented it already, as you show in your question. So what's the real question? — JB Nizet
– JB Nizet, Commented Sep 22, 2012 at 22:18

PermGenError · Accepted Answer · 2012-09-22 22:17:28Z

2

in string.substring(a,b) first argument is zero indexed and 2nd argument is 1 indexed. for example:

      "smiles".substring(1, 5) returns "mile"

if you wanna get al from the string "alphabet" you'd have to do

         LinkedHashMap<String, Integer> ht = new LinkedHashMap<String, Integer>();
 int value=0;
     for(int i=0; i<str.length()-1; i++) {
         ht.put(str.substring(i, i+2), value);
         value++;
     }
     Set<String> set = ht.keySet();
     Iterator<String> itr = set.iterator();
     while(itr.hasNext()) {
         String d = itr.next();
         System.out.println(d+ " "+ ht.get(d));
     }
    }

OUTPUT: al 0 lp 1 ph 2 ha 3 ab 4 be 5 et 6

edited Sep 22, 2012 at 22:17

answered Sep 22, 2012 at 22:02

PermGenError

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2 Comments

ellangog Over a year ago

I get String index out of bounds because when it gets to end I have an issue

Rohit Jain Over a year ago

In for: - (i < str.length() - 1)

Subir Kumar Sao · Accepted Answer · 2012-09-22 22:05:17Z

0

int value = 0;
for (int i = 0; i < str.length()-1; i++) {
  ht.put(str.substring(i, i + 2), value);
  value++;
}

answered Sep 22, 2012 at 22:05

Subir Kumar Sao

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5 Comments

PermGenError Over a year ago

why are you initilizing value to 0 on every iteration ?

ellangog Over a year ago

Thanks, I ran the code and got this ha: 3 lp: 1 be: 5 ab: 4 et: 6 al: 0 ph: 2

ellangog Over a year ago

I want it be on order is that possible? You guys are awesome btw

Subir Kumar Sao Over a year ago

Use LinkedHashMap if you want it to be ordered on insertion.

ellangog Over a year ago

How would that work? Can you refer me to some reading material. THanks

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