Remove trailing comma from comma-separated string

To remove the ", " part which is immediately followed by end of string, you can do:

str = str.replaceAll(", $", "");

This handles the empty list (empty string) gracefully, as opposed to lastIndexOf / substring solutions which requires special treatment of such case.

Example code:

String str = "kushalhs, mayurvm, narendrabz, ";
str = str.replaceAll(", $", "");
System.out.println(str);  // prints "kushalhs, mayurvm, narendrabz"

---

NOTE: Since there has been some comments and suggested edits about the ", $" part: The expression should match the trailing part that you want to remove.

• If your input looks like "a,b,c,", use ",$".
• If your input looks like "a, b, c, ", use ", $".
• If your input looks like "a , b , c , ", use " , $".

I think you get the point.

You can use this:

String abc = "kushalhs , mayurvm , narendrabz ,";
String a = abc.substring(0, abc.lastIndexOf(","));

Use Guava to normalize all your commas. Split the string up around the commas, throw out the empties, and connect it all back together. Two calls. No loops. Works the first time:

import com.google.common.base.Joiner;
import com.google.common.base.Splitter;

public class TestClass {

    Splitter splitter = Splitter.on(',').omitEmptyStrings().trimResults();
    Joiner joiner = Joiner.on(',').skipNulls();

    public String cleanUpCommas(String string) {
        return joiner.join(splitter.split(string));
    }

}



public class TestMain {

    public static void main(String[] args) {
        TestClass testClass = new TestClass();

        System.out.println(testClass.cleanUpCommas("a,b,c,d,e"));
        System.out.println(testClass.cleanUpCommas("a,b,c,d,e,,,,,"));
        System.out.println(testClass.cleanUpCommas("a,b,,, ,c,d,  ,,e,,,,,"));
        System.out.println(testClass.cleanUpCommas("a,b,c,d,  e,,,,,"));
        System.out.println(testClass.cleanUpCommas(",,, ,,,,a,b,c,d,  e,,,,,"));
    }

}

Output:

a,b,c,d,e
a,b,c,d,e
a,b,c,d,e
a,b,c,d,e
a,b,c,d,e

Personally, I hate futzing around with counting limits of substrings and all that nonsense.