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Given a string = "test20190906.pdf", how can I get only "test.pdf" such that it removes the date from the string by using string.replace or remove ?

Considering the format will always be filename + date + .extension.

There are a lot of good answers, but I want present one more. It'll work if filename contains digits not only in date part. I assume that date is always appears before extension and has fixed length.

s.replaceAll("\d8\.pdf", ".pdf");

And if the file extension varies then you could do some additional work:

public static String removeDate(String s) 
 final String extension = s.substring(s.lastIndexOf("."));
 final String pattern = "\d8\" + extension;

 return s.replaceAll(pattern, extension);


public static void main(String args[])

 System.out.println(removeDate("test20190101.pdf"));
 System.out.println(removeDate("123123test20190101.txt"));
 System.out.println(removeDate("123te11st20190101.csv"));

This can be done with the regexp only, but at the cost of readability.

You can use a regex to remove consecutive digits that resemble a date in any format provided the filename is appended immediately by the date.

"test20190906.pdf".replaceAll("[0-9]8\.", "."));

I see previous answers and that answers does not work if you got other numbers in file name for example: 01_test20190913.pdf

In that case solution will be

String file = "01_test20190913.pdf";
System.out.println(file.substring(0, file.length() - 12)+".pdf");

here i take the first part of string without last 12 characters and add ".pdf"

Assuming the date contains only numbers, you can use regex to replace numbers, e.g.:

String fileNameWithDate = "test20190906.pdf";
String fileName = fileNameWithDate.replaceAll("[0-9]+", ""));
System.out.println(fileName);

If the format of date is "yyyyMMdd" then I suggest go for the simplest solution as also given by @pavelbere. But this solution also assumes that the date always appends in the end of the filename.

String file = "test20190906.pdf"; 
String fileName = file.substring(0, file.length() - 12)+".pdf";

If you want to remove the dates only from the String then you can take a look on the solution (Assuming the date will come just before the .pdf) :

 String fileNameWithDate = "te3st320190906.pdf";

 StringBuilder sb = new StringBuilder(fileNameWithDate).replace(fileNameWithDate.indexOf(".pdf") - 8,
 fileNameWithDate.indexOf(".pdf"), "");
 System.out.println(sb.toString());

Output:

te3st3.pdf