How to extract a subString from android java String?

Question

I tried to extract Sub-String from java string, but failed. i tried like this

String text = "audios/{any_number} any_audio_name.mp3";
text= text.substring(text.indexOf('/'), text.indexOf('3')-2);

Updated

I need String contains only any_audio_name and removing audios/ , any number e.g. {123} and .mp3

For example audios/{211} new school poem.mp3 to new school poem

If you don't want to include the `/`, use `text.indexOf('/')+1`. And better to use `lastIndexOf('.')` than relying on subtracting 2. — Andy Turner, May 29 '19 at 19:18
If you're working with file names, Apache Commons has [FileNameUtils](https://commons.apache.org/proper/commons-io/javadocs/api-2.5/org/apache/commons/io/FilenameUtils.html) that do the hard work for you and would scale better. — Compass, May 29 '19 at 19:19
Regex is overkill ... anyway, duplicate https://stackoverflow.com/questions/924394/how-to-get-the-filename-without-the-extension-in-java — second, May 29 '19 at 19:42

Qingfei Yuan · Answer 1 · 2019-05-29T20:06:13.710

1

Use regex seems fit here.

public class MyMain{
    public static void main(String args[]) {
        String line = "audios/any_audio_name.mp3";
        String pattern = "audios\\/(.*)\\.mp3";

        // Create a Pattern object
        Pattern r = Pattern.compile(pattern);

        // Now create matcher object.
        Matcher m = r.matcher(line);

        if (m.find()) {
            System.out.println("Found value: " + m.group(1));
        } else {
            System.out.println("NO MATCH");
        }
    }
}

edited May 29 '19 at 20:06

answered May 29 '19 at 19:21

Qingfei Yuan

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`"^.*/(.*)\\..*$"` would fit more cases. You can't use `\/`, it's either `\\/` or `/`. And use `group(1)`. – Paul Lemarchand May 29 '19 at 19:27
String pattern = "audios\/(.*).mp3"; give "Illegal escape character in string literal" error – Attaullah May 29 '19 at 19:30
I/System.out: NO MATCH – Attaullah May 29 '19 at 19:39
1

Simpler to just use replace, e.g. `text = text.replaceFirst("^(?:.*?/)?([^/]+?)(?:\\.[^./]*?)?$", "$1");` --- See [demo](https://regex101.com/r/6sz0lj/1) on regex101 – Andreas May 29 '19 at 19:39
@Andreas if text contains like audios/{123} audio_name.mp3 and i need just name like audio_name what will i do??? – Attaullah May 29 '19 at 19:50
1

@Attaullah 1) Learn regex. 2) Update the pattern in the replace call. – Andreas May 29 '19 at 19:53
Pattern miss some java string in List. when Capital MP3 instead of mp3 @Andreas – Attaullah May 29 '19 at 21:41
@Attaullah Since [my pattern](https://stackoverflow.com/questions/56367130/how-to-extract-a-substring-from-android-java-string/56367224?noredirect=1#comment99337877_56367224) doesn't specify `mp3`, it cannot care about lower- vs upper-case, so it simply cannot match differently just because `.mp3` is changed to `.MP3`. Try again. – Andreas May 29 '19 at 22:10

score 1 · Answer 2 · answered May 29 '19 at 19:41

1

This answer might helpful

String text = "audios/any_audio_name.mp3";
text= text.substring(text.indexOf('/')+1, text.indexOf('.'));

answered May 29 '19 at 19:41

Malinda

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this also work but previous one give me answer first – Attaullah May 29 '19 at 19:45
You'd probably want to use `lastIndexOf` for both of them. Whether changing that or not, you should also cross your fingers and hope to never see input like `foo.bar/file_without_extension` – Andreas May 29 '19 at 19:48
Yes you correct but in here his requirement is to get name of mp3 file.so most probably that file come with .mp3 extention and he describe file path as audios – Malinda May 29 '19 at 19:53
Actually i read XML data is in server in listview, first i filtered (whole line into name) and then showing it in listview. – Attaullah May 29 '19 at 20:47

score 1 · Answer 3 · answered May 29 '19 at 20:19

1

For Your Edited Question.Following Code segment will help you but here i assume that there will be no number within "any_audio_name"

String text = "audios/{any_number}any_audio_name.mp3";
text= text.substring(text.indexOf('/')+1, text.indexOf('.')).replaceAll("[\\d.]", "");;

answered May 29 '19 at 20:19

Malinda

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but {} is remaining – Attaullah May 29 '19 at 20:32
.replaceAll("\\{|\\}|[\\d.]",""); is use this – Attaullah May 29 '19 at 20:40

score 0 · Answer 4 · answered May 29 '19 at 20:40

0

Thanks for everyone, who give me idea for solving this issue.

 String text = "audios/{any_number}any_audio_name.mp3";
 text= text.substring(text.indexOf('/')+1, text.indexOf('.')).replaceAll("\\{|\\}|[\\d.]","");
 System.out.println(text);

answered May 29 '19 at 20:40

Attaullah

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How to extract a subString from android java String?

4 Answers4