a simple question

[gayathriy Nandakumar]

hi.. i have a question regarding Swapping of characters in a string that uses stringbuffer..
like
StringBuffer codestring="abcdefghijkl"..how do i swap the char 'a' with 'd' in the string so that final string is like..
codestring="dbcaefghijkl"..

[vidya sagar]

Try this

StringBuffer sb = new StringBuffer("abcdefghijkl");
sb = new StringBuffer(sb.toString().replaceAll("a","d"));

[Ankur Sharma]

Originally posted by vidya sagar:
Try this

StringBuffer sb = new StringBuffer("abcdefghijkl");
sb = new StringBuffer(sb.toString().replaceAll("a","d"));

Dear Vidya,

This will only replace 'a' to 'd' not the 'd' to 'a'. He might want to replace these 2 chars simultaneously.

[vidya sagar]

This will only replace 'a' to 'd' not the 'd' to 'a'. He might want to replace these 2 chars simultaneously.

Hi Ankur

i just seen how do i swap the char 'a' with 'd' in the string this sentence.Poster doesnot say about vice versa.If he/she wants wants then we will come with some other solution.

[Ulf Dittmer]

how do i swap the char 'a' with 'd' in the string this sentence.Poster does not say about vice versa

I'm not a native English-speaker, but I think swap is not the same as replace, which is what you are referring to. Swap indeed means that the two items in questions switch their places, so there really is no "vice versa" - both happen at the same time.

One possibility would be to replace 'a' by a completey different character -which you can be sure does not otherwise occur in the string-, then replace 'd' by 'a', and then the other character by 'd'.

[vidya sagar]

Ulf,You are correct.But Anyway i am looking for the real poster to reply on this regard.BY the way i am also not native Speaker of English.

[vidya sagar]

waiting for response from topic starter, anyway have this too

   String tmp =  new StringBuffer("abcdefghijkl").toString(); 
   System.out.println(swap(tmp,"a","d"));
 
   public static String swap(String tmp,String first,String second)
   {
StringBuffer sb = new StringBuffer();
for(int i=0;i<tmp.length();i++)
{
if(first.equals(tmp.substring(i,i+1)))
{
sb.append(second);
}
else if(second.equals(tmp.substring(i,i+1)))
{
sb.append(first);
}
else
{
sb.append(tmp.substring(i,i+1));
}
}
return sb.toString();
}   

Hope it is little big....

[karthikeyan Chockalingam]

You may use this version if you like it

public static void main(String[] args) throws Exception {
 
        
StringCharacterIterator iter=new StringCharacterIterator("abcdefghijkl");
StringBuffer sbuff=new StringBuffer();

for(char curr=iter.first();CharacterIterator.DONE != curr;curr=iter.next()){
sbuff.append(getReplacement(curr));
}

System.out.println(sbuff.toString());

    }

private static char  getReplacement(char ch){

switch(ch){
case 'a':
return 'd';
case 'd':
return 'a';
}

return ch;

}

[ July 13, 2006: Message edited by: karthi keyan ]

[abhijit Ohal]

bit more simpler method

 
 public static String swap(String OriginalString, String s1, String s2) {
        StringBuffer sb = new StringBuffer(OriginalString);
        int pos1 = sb.indexOf(s1);
        int pos2 = sb.indexOf(s2);
        sb.replace(pos1,pos1+1,s2);
        sb.replace(pos2,pos2+1,s1);
 
        return sb.toString();
    }
 

 

[vidya sagar]

Really Simpler One.with one drawback,Suppose swap characters occurs more than once it will not work. Eg:abcdefghijkla

[fred rosenberger]

you will also note that the original poster said

how do i make this:
abcdefghijkl

look like this:
dbcaefghijkl

note that here it's quite clear they mean "make all 'a's in the original into 'd's, and all 'd's into 'a's...

[Stan James]

Here's a replace based on REXX syntax. Note how it can be used to rearrange a string. You could use that to swap characters based on position. I bet it would not give correct results on translate AD to DA.

This is very old code with a semi-hungarian prefix naming thing that I outgrew ...

/**
 * Translates characters in a string to other characters.  For each
 * character of the input, if that character is found in InTable,
 * it is replaced with the character from OutTable. Translate can
 * also be used to rearrange the order of characters.  Based on REXX.
 * <pre>
 * translate( A:\ONE.TWO, /_, \. )               -> A:/ONE_TWO
 * tranlsate( GHIJABDE, 12/31/1999, ABCDEFGHIJ ) -> 19991231
 * </pre>
 * Note: If OutTable is shorter than InTable, OutTable is padded with
 * spaces, so the extra characters of InTable are replaced by spaces.
 * @return String
 * @param aString String
 * @param aOutTable String
 * @param aInTable String
 */
public static String translate(String aString, String aOutTable, String aInTable)
{
   String lResult = aString;
   aOutTable = left(aOutTable, aInTable.length() );
   for ( int i = 0; i < aInTable.length(); i++ )
   {
      lResult = lResult.replace( aInTable.charAt( i ),
                                 aOutTable.charAt( i ) );
   }
   return lResult;
}

The left() method pads or truncates as necessary to left justify.