How to replace a substring of a string [duplicate]

Question

Assuming I have a String string like this:

"abcd=0; efgh=1" 

and I want to replace "abcd" by "dddd". I have tried to do such thing:

string.replaceAll("abcd","dddd"); 

It does not work. Any suggestions?

EDIT: To be more specific, I am working in Java and I am trying to parse the HTML document, concretely the content between <script> tags. I have already found a way how to parse this content into a string:

 if(tag instanceof ScriptTag){         if(((ScriptTag) tag).getStringText().contains("DataVideo")){             String tagText = ((ScriptTag)tag).getStringText();       } } 

Now I have to find a way how to replace one substring by another one.

Answer 1

You need to use return value of replaceAll() method. replaceAll() does not replace the characters in the current string, it returns a new string with replacement.

• String objects are immutable, their values cannot be changed after they are created.
• You may use replace() instead of replaceAll() if you don't need regex.

    String str = "abcd=0; efgh=1";     String replacedStr = str.replaceAll("abcd", "dddd");      System.out.println(str);     System.out.println(replacedStr); 

outputs

abcd=0; efgh=1 dddd=0; efgh=1 

Answer 2

2 things you should note:

1. Strings in Java are immutable to so you need to store return value of thereplace method call in another String.
2. You don't really need a regex here, just a simple call to String#replace(String) will do the job.

So just use this code:

String replaced = string.replace("abcd", "dddd");