Deleting exact match String from text file

Question

I am trying to remove a specific string in my text file. Current code gets the line one by one until 50 is hit. I am trying to remove the string (EXACT MATCH!) in the notepad, but not sure how to do so.

Scanner input = new Scanner(new File("C:\\file.txt"));
            int counter = 0;
            while(input.hasNextLine() && counter < 50) {
                counter++;
                String tempName = input.nextLine();
                //perform my custom code here
                //somehow delete tempName from the text file (exact match)
            }

I have tried input.nextLine().replaceFirst(tempName, ""); without any luck

You need to write the changed line back to the file if you need to see the change in the file. — SomeDude, Jun 06 '21 at 13:20

score 0 · Accepted Answer · edited Jun 06 '21 at 16:58

0

If you are using Java 8, You can do something like below using java.nio package:

Path p = Paths.get("PATH-TO-FILE");
List<String> lines = Files.lines(p)
              .map(str -> str.replaceFirst("STRING-TO-DELETE",""))
              .filter(str -> !str.equals(""))
              .collect(Collectors.toList());
Files.write(p, lines, StandardCharsets.UTF_8);

edited Jun 06 '21 at 16:58

Mark Rotteveel

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answered Jun 06 '21 at 13:35

Tarun

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It does not work for me. Are you sure this is correct? – beastil34 Jun 06 '21 at 13:40
OP has already tried with replaceFirst so how does this help? – Joakim Danielson Jun 06 '21 at 13:40
provide the sample input and expected result. – Tarun Jun 06 '21 at 13:42
Code is being executed, but it does not remove the string from my text file. I added a log to check. – beastil34 Jun 06 '21 at 13:43
@TarunVerma Thank you. Is there a way to remove the entire line instead of replacing it with nothing? Line still exists, need it removed if possible. – beastil34 Jun 06 '21 at 13:54
@beastil34 : You mean empty lines to be removed? – Tarun Jun 06 '21 at 13:56
@beastil34 : Updated answer to remove empty lines. – Tarun Jun 06 '21 at 13:58
@TarunVerma Yes! :) – beastil34 Jun 06 '21 at 13:58
@beastil34 Done. Give a thumbs up if you like the answer. – Tarun Jun 06 '21 at 13:59
Thank you, works as intended. I have marked it as correct answer. Sadly I can not upvote due to not having 15 rep. Thanks again. – beastil34 Jun 06 '21 at 14:01

score 0 · Answer 2 · edited Jun 06 '21 at 16:59

0

Below line replaces "the" with "**"

Pattern pattern = Pattern.compile("the", Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(tempName);
String repalcedvalue = matcher.replaceAll("**");

edited Jun 06 '21 at 16:59

Mark Rotteveel

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191
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answered Jun 06 '21 at 16:00

Nirmitha Kadaru

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Deleting exact match String from text file

2 Answers2