How do I replace string in string

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Good day. So I want to ask you how to change substring in a string that I got from JEditorPane.

Im making a program for chords changin according to this: C to C# , C# to D, D# to E , E to F, F to F# , F# to G , G to G#,...

I wrote code,but it allways goes from begginging till the end.For example, if I write in JEditorPane:

" C D# E " it all goes to F#. How can I just make changes for 1 step( just C to C# , D# to E , E to F)?

Java

if (event.getSource()== ok)
			{
				Object contents = akordib.getSelectedItem();
				
				
				
				
				if (contents == "+1 step")
				{
					final = textPanel.getText();
					
					if (final.contains(" C ") == true)
					{
						final = final.replaceAll(" C" , " C#");
						textPanel.setText(final);
					}
					
					if (final.contains(" C# ") == true)
					{
						final = final.replaceAll(" C# ", " D ");
						textPanel.setText(final);
					}
				}	
    				}

Posted 28-Oct-14 9:29am

Vukasin Vulovic

Updated 28-Oct-14 9:36am

PIEBALDconsult

v2

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

PIEBALDconsult · Accepted Answer · 2014-10-28T09:37:00

Solution 1

Perform the replacements in reverse order. And you may want to use intermediate values.

And do you really need to check to see whether or not the string contains the value first?

I recommend performing the setText only at the end.

As you have it, you'll be scanning the string a great many times; I would write a custom method that scans it only once.

Posted 28-Oct-14 9:37am

PIEBALDconsult

Updated 28-Oct-14 9:44am

v3

Comments

Sergey Alexandrovich Kryukov 28-Oct-14 15:40pm

This time, I voted 5 without even looking at the code, because I know that this is a very common issue and the resolution; hope you identified it correctly.
—SA

PIEBALDconsult 28-Oct-14 15:46pm

Ooooh, risky. :D

Sergey Alexandrovich Kryukov 28-Oct-14 15:49pm

I know. :-)
I though I could trust you on that.
You know me; in case someone proves you wrong, I'll readily admit my mistake and down-vote, but I'm pretty much sure you are right here. :-)
—SA

PIEBALDconsult 28-Oct-14 15:51pm

Despite all the evidence to the contrary?

Sergey Alexandrovich Kryukov 28-Oct-14 15:57pm

I did not get it, or you did not understand me.
I mean, my opinion was based on the known problem and knowing some your skills by previous answers.
If I'm wrong here, I'll follow whatever is proven to be correct to me. No "despite".
—SA

PIEBALDconsult 28-Oct-14 17:12pm

Don't worry, just engaging in some self-deprecation.

Sergey Alexandrovich Kryukov 28-Oct-14 17:25pm

:-)

Vukasin Vulovic 28-Oct-14 16:04pm

Ok,but how to make a method that goes just once through it? Is this corect?
for(i=0;i<1;i++) ?

[no name] 28-Oct-14 16:09pm

OP: Don't forget the accidental ♯, ♯♯, ♭, ♭♭ and last but not least the ♮
;)

Vukasin Vulovic 28-Oct-14 16:10pm

Thanks guys

Maciej Los 28-Oct-14 16:59pm

Bruno, are you a musician?

[no name] 28-Oct-14 17:03pm

Yes ;)
My first Instrument is drums and singing (really a real time parallel process:) ) and then a Little bit piano and guitar.

In singing lessons I had to learn
http://en.wikipedia.org/wiki/Circle_of_fifths[^]
Forward and backward. I'm still asking me why *lol*

You are misician too?

Maciej Los 28-Oct-14 17:13pm

I wouldn't call myself a musician, but... from time to time i play on acoustic guitar (autodidact)...

[no name] 28-Oct-14 17:15pm

Musician is musician, I'm also far far far away from beeing good, only enjoy it beside my technical Job.

Better we stop the conversation here, otherwise we disturb others

Maciej Los 28-Oct-14 17:23pm

My experience is limited to few guitar tricks ;)
Without song book i'm blind and deaf...

Maciej Los 28-Oct-14 16:59pm

Sounds like chorus ;)
+5!

PIEBALDconsult · Accepted Answer · 2014-10-28T10:44:00

Here's a quick rough one-pass algorithm implemented in C# (I don't know Java).
Things to be altered/improved are the Dictionary (lookup table) and, as written, it requires that the string end with whitespace (left as an exercise).
You would need a different Dictionary for each step.

C#

System.Collections.Generic.Dictionary<string,string> rep =
  new System.Collections.Generic.Dictionary<string,string>() ;
rep [ "C"  ] = "C#" ;
rep [ "C#" ] = "D"  ;
rep [ "D#" ] = "E"  ;
rep [ "E"  ] = "F"  ;
rep [ "F"  ] = "F#" ;
rep [ "F#" ] = "G"  ;
rep [ "G"  ] = "G#" ;

string muse = " C D# E " ;

System.Text.StringBuilder token  = new System.Text.StringBuilder ( muse.Length ) ;
System.Text.StringBuilder result = new System.Text.StringBuilder ( muse.Length ) ;

for ( int i = 0 ; i < muse.Length ; i++ )
{
  char ch = muse [ i ] ;

  if ( !System.Char.IsWhiteSpace ( ch ) )
  {
    token.Append ( ch ) ;
  }
  else
  {
    if ( token.Length > 0 )
    {
      string tok = token.ToString() ;

      if ( rep.ContainsKey ( tok ) )
      {
        result.Append ( rep [ tok ] ) ;
      }
      else
      {
        result.Append ( tok ) ;
      }

      token.Length = 0 ;
    }

    result.Append ( ch ) ;
  }
}

How do I replace string in string

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