68

I got String from the database which have multiple commas (,) . I want to remove the last comma but I can't really find a simple way of doing it.

What I have: kushalhs, mayurvm, narendrabz,

What I want: kushalhs, mayurvm, narendrabz

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1

17 Answers 17

Reset to default
167

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.

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5 Comments

what is the use of $ ? does it represent lasi index of ,
Not exactly "last match of". It is a special symbol for matching the end of the string.
str.replaceAll(",$",""); DOES NOT remove the last comma. You need to add a space between the comma and the dollar sign for it to work: str.replaceAll(", $",""); WORKS. Tested as of Java 7.0.
@Lemmings19, depends on the what string you start with of course. It does remove it from the sample strings that the OP provided, doesn't it? To be a bit more general one could use the regexp \s*,\s*$.
@aioobe Ah... I figured it out. >.< I had a trailing space that I wasn't seeing. It all makes sense now. It sure didn't last night! Human error. I can't brain. Your provided RegEx works, just as it should.
13

You can use this:

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

This is bit dangerous:if you use abc = "kushalhs , mayurvm , narendrabz" This will result in "kushalhs , mayurvm"
8

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.

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Comments

3

For more than one commas

            String names = "Hello,World,,,";
    System.out.println(names.replaceAll("(,)*$", ""));

Output: Hello,World

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Comments

3 
(^(\s*?\,+)+\s?)|(^\s+)|(\s+$)|((\s*?\,+)+\s?$)

Regexr

ex:

a, b, c
, ,a, b, c, 
,a, b, c   ,
,,a, b, c, ,,,
, a, b, c,    ,
    a, b, c     
     a, b, c ,,
, a, b, c, 
, ,a, b, c, ,
 , a, b, c , 
,,, a, b, c,,, 
,,, ,,,a, b, c,,, ,,,
,,, ,,, a, b, c,,, ,,,
 ,,,a, b, c ,,,
 ,,,a, b, c,,, 
   a, b, c

becomes:

a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
a, b, c
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Comments

3

And one more ... this also cleans internal commas mixed with whitespace:

From , , , ,one,,, , ,two three, , , ,,four, , , , , to one,two three, four

text.replaceAll("^(,|\\s)*|(,|\\s)*$", "").replaceAll("(\\,\\s*)+", ",");
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Comments

2

Check if str.charAt(str.length() -1) == ','. Then do str = str.substring(0, str.length()-1)

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2 Comments

breaks on the empty string (StringIndexOutOfBoundsException)
These are the boundary conditions which I thought you were handling anyway. Like at firt line of you function you should have check if(string == null || string.trim().equals("")) return;
2

I'm late on this thread but hope it will help to some one.......

String abc = "kushalhs , mayurvm , narendrabz ,";

if(abc.indexOf(",") != -1){
    abc = abc.substring(0,abc.length() - 1);
}
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Comments

2

You can do something like using join function of String class.

import java.util.Arrays;
import java.util.List;

public class Demo {

    public static void main(String[] args) {
        List<String> items = Arrays.asList("Java", "Ruby", "Python", "C++");
        String output = String.join(",", items);
        System.out.println(output);
    }

}
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Comments

1

This method is in BalusC's StringUtil class. his blog

i use it very often and will trim any string of any value:

/**
 * Trim the given string with the given trim value.
 * @param string The string to be trimmed.
 * @param trim The value to trim the given string off.
 * @return The trimmed string.
 */
public static String trim(String string, String trim) {
    if (string == null) {
        return null;
    }

    if (trim.length() == 0) {
        return string;
    }

    int start = 0;
    int end = string.length();
    int length = trim.length();

    while (start + length <= end && string.substring(
            start, start + length).equals(trim)) {
        start += length;
    }
    while (start + length <= end && string.substring(
            end - length, end).equals(trim)) {
        end -= length;
    }

    return string.substring(start, end);
}

ex:

trim("1, 2, 3, ", ", ");
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1 Comment

That would remove leading ", " from the actual values though ;-)
1 
    String str = "kushalhs , mayurvm , narendrabz ,";
    System.out.println(str.replaceAll(",([^,]*)$", "$1"));
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Comments

0

You can do something like this using 'Java 8'

private static void appendNamesWithComma() {
    List<String> namesList = Arrays.asList("test1", "tester2", "testers3", "t4");
    System.out.println(namesList.stream()
                                .collect(Collectors.joining(", ")));

}
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1 Comment

This example worked for me.
0

You can try with this, it worked for me:

if (names.endsWith(",")) {
    names = names.substring(0, names.length() - 1);
}

Or you can try with this too:

string = string.replaceAll(", $", "");
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Comments

0 
public static String removeExtraCommas(String entry) {
    if(entry==null)
        return null;

    String ret="";
    entry=entry.replaceAll("\\s","");
    String arr[]=entry.split(",");
    boolean start=true;
    for(String str:arr) {
        if(!"".equalsIgnoreCase(str)) {
            if(start) {
                ret=str;
                start=false;
            }
            else {
            ret=ret+","+str;
            }
        }
    }               
    return ret;

}
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Comments

0

i am sharing code form my project using regular expression you can do this...

String ChildBelowList = "";

    if (!Childbelow.isEmpty()) {
        for (int iCB = 0; iCB < Childbelow.size(); iCB++) {

            ChildBelowList = ChildBelowList += Childbelow.get(iCB) + ",";



        }
        ChildBelowList = ChildBelowList.replaceAll("(^(\\s*?\\,+)+\\s?)|(^\\s+)|(\\s+$)|((\\s*?\\,+)+\\s?$)", "");

        tv_childbelow.setText(ChildBelowList);

    } else {
        ll_childbelow.setVisibility(View.GONE);
    }
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Comments

-1

Or something like this:

private static String myRemComa(String input) { 
        String[] exploded = input.split(",");
        input="";
        boolean start = true;
        for(String str : exploded) {

         str=str.trim();
         if (str.length()>0) {
             if (start) {
                 input = str;
                    start = false;
                } else {
                    input = input + "," + str;
                }
         }
        }

        return input;
    }
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Comments

-2 
package com.app;

public class SiftNumberAndEvenNumber {

    public static void main(String[] args) {

        int arr[] = {1,2,3,4,5};
        int arr1[] = new int[arr.length];
        int shiftAmount=3;
        
        for(int i = 0; i < arr.length; i++){
            int newLocation = (i + (arr.length - shiftAmount)) % arr.length;
            arr1[newLocation] = arr[i];
            
        }
        for(int i=0;i<arr1.length;i++) {
            if(i==arr1.length-1) {
                System.out.print(arr1[i]);
            }else {
                System.out.print(arr1[i]+",");
            }
        }
        System.out.println();
        for(int i=0;i<arr1.length;i++) {
            if(arr1[i]%2==0) {
                System.out.print(arr1[i]+" ");
            }
        }
    }
}
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2 Comments

This is used for sifting numbers based on index in Integer array "int arr[] = {1,2,3,4,5};"
Remove cama( , ) from end of the output.

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