How to get string between a character and first occurrence of double quotes?

Question

I am trying to get tvg-logo string( http://awebsite/logos/TestChannel.png ) but my current code only works on case one.For case 2 and 3 inputs the code outputs not only the tvg-logo value but also the rest of string after it!could you guys show me how to get ONLY tvg-logo url in all these case ?Thanks

public class HelloWorld {
  public static void main(String[] args) {

    //case 1:
    //String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\"";
    //case 2:
    //String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\" group-title=\"Movies\"";
    //case 3:
    String s="-1 tvg-logo=\"http://awebsite/logos/TestChannel.png\" tvg-name=\"Test Channel\" group-title=\"Movies\"";

    String icon = s.substring(s.indexOf("tvg-logo") + "tvg-logo".length()).replace("=", "").replace("\"", "").replace("\n", "");

    System.out.println("Logo:"+icon);
  }
}

output for case 3 input:

Logo:http://awebsite/logos/TestChannel.png tvg-nameTest Channel group-titleMovies

Expected output for all types of input cases:

Logo:http://awebsite/logos/TestChannel.png

Answer 1

You need to add a second parameter to the substring call to limit the length of the subtring, like so:

public class Main {
  public static void main(final String[] args) {

    // case 1:
    // String s = "-1 tvg-name=\"Test Channel\"
    // tvg-logo=\"http://awebsite/logos/TestChannel.png\"";
    // case 2:
    String s =
            "-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\" group-title=\"Movies\"";
    // case 3:
    // String s =
    // "-1 tvg-logo=\"http://awebsite/logos/TestChannel.png\" tvg-name=\"Test
    // Channel\" group-title=\"Movies\"";

    String tvgLogo = "tvg-logo=\"";
    int tvgLogoIndex = s.indexOf(tvgLogo) + tvgLogo.length();
    String icon = s.substring(tvgLogoIndex, s.indexOf('"', tvgLogoIndex)).replace("=", "")
            .replace("\"", "").replace("\n", "");

    System.out.println("Logo:" + icon);
  }
}

The s.indexOf('"', tvLogoIndex) call searches for the double quote that closes off the tvg-logo attribute so that you select only the logo url.

Note that if you're parsing HTML documents there are probably cleaner solutions than using subtrings.

Answer 2

Here's another using regex.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class HelloWorld {

    public static void main(String[] args) {

        String s="-1 tvg-logo=\"http://awebsite/logos/TestChannel.png\" tvg-name=\"Test Channel\" group-title=\"Movies\"";

        // Pattern matcher looking for shortest string surrounded with escaped quotes
        // following tvg-logo=\"
        // Two groups, first is string tvg-logo and second is the logo string
        Matcher tvgMatcher = Pattern.compile("(tvg-logo)=\\\"([^\\\"]+)\\\"").matcher(s);

        while (tvgMatcher.find()) {
            String icon = tvgMatcher.group(2);
            System.out.println(tvgMatcher.group(1)+": "+icon);
        }
    }   
}

Outputs

tvg-logo: http://awebsite/logos/TestChannel.png

Answer 3

public class HelloWorld
{
    public static void main (String[] args) throws java.lang.Exception
    {
        //case 1:
    //String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\"";
    //case 2:
    //String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\" group-title=\"Movies\"";
    //case 3:
    String s="-1 tvg-logo=\"http://awebsite/logos/TestChannel.png\" tvg-name=\"Test Channel\" group-title=\"Movies\"";

    String icon="";
    String[] splited = s.split("\\s+");
    for(int i=0;i<splited.length;i++){
        if(splited[i].contains("tvg-logo")){
            icon = splited[i].substring(10);
        }
    }
    //String icon = s.substring(s.indexOf("tvg-logo") + "tvg-logo".length()).replace("=", "").replace("\"", "").replace("\n", "");

    System.out.println("Logo:"+icon);
    }
}

Answer 4

You could insert the line icon=icon.substring(0,icon.indexOf(" ")); to extract it.

public static void main(String[] args) {

    //case 1:
    //String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\"";
    //case 2:
    //String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\" group-title=\"Movies\"";
    //case 3:
    String s="-1 tvg-logo=\"http://awebsite/logos/TestChannel.png\" tvg-name=\"Test Channel\" group-title=\"Movies\"";
    String icon = s.substring(s.indexOf("tvg-logo") + "tvg-logo".length()).replace("=", "").replace("\"", "").replace("\n", "");
    icon=icon.substring(0,icon.indexOf(".png")+4);
    System.out.println("Logo:"+icon);
  }

Answer 5

If I am right, this is what happens in you code:

• your string builder logic ("s.substring ....") works for case 1 because it fits quite well this case;
• in case 2, you have also "group-title" and you don't manage this case, thus is still continues to appear on the final string;
• in case 3, the situation is the same as the case 2 and moreover tvg-logo and tvg-name are in different orders.

At the end, your code makes a sort of overfitting for the case 1. Keep the same order inside each string of each case and manage the case in which there is group-title at the end of the string.

Try this (I did not test it):

boolean groupFound = false;
//case 1:
//String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\"";
//case 2: {
//String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\" group-title=\"Movies\"";
//groupFound = true;}
//case 3: {
String s="-1 tvg-name=\"Test Channel\" tvg-logo=\"http://awebsite/logos/TestChannel.png\"  group-title=\"Movies\"";
groupFound = true; }

String icon = s.substring(s.indexOf("tvg-logo") + "tvg-logo".length()).replace("=", "").replace("\"", "").replace("\n", "");
if(groupFound){
   String group = "group-title";
   int groupIndex = String.indexOf(group);
   String newIcon = icon.substring(0, groupIndex);
}