Remove Last Comma from a string
JavascriptJavascript Problem Overview
Using JavaScript, how can I remove the last comma, but only if the comma is the last character or if there is only white space after the comma? This is my code. I got a working fiddle. But it has a bug.
var str = 'This, is a test.';
alert( removeLastComma(str) ); // should remain unchanged
var str = 'This, is a test,';
alert( removeLastComma(str) ); // should remove the last comma
var str = 'This is a test, ';
alert( removeLastComma(str) ); // should remove the last comma
function removeLastComma(strng){
var n=strng.lastIndexOf(",");
var a=strng.substring(0,n)
return a;
}
Javascript Solutions
Solution 1 - Javascript
This will remove the last comma and any whitespace after it:
str = str.replace(/,\s*$/, "");
It uses a regular expression:
-
The
/
mark the beginning and end of the regular expression -
The
,
matches the comma -
The
\s
means whitespace characters (space, tab, etc) and the*
means 0 or more -
The
$
at the end signifies the end of the string
Solution 2 - Javascript
you can remove last comma from a string by using slice() method, find the below example:
var strVal = $.trim($('.txtValue').val());
var lastChar = strVal.slice(-1);
if (lastChar == ',') {
strVal = strVal.slice(0, -1);
}
Here is an Example
function myFunction() {
var strVal = $.trim($('.txtValue').text());
var lastChar = strVal.slice(-1);
if (lastChar == ',') { // check last character is string
strVal = strVal.slice(0, -1); // trim last character
$("#demo").text(strVal);
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<p class="txtValue">Striing with Commma,</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
Solution 3 - Javascript
function removeLastComma(str) {
return str.replace(/,(\s+)?$/, '');
}
Solution 4 - Javascript
In case its useful or a better way:
str = str.replace(/(\s*,?\s*)*$/, "");
It will replace all following combination end of the string:
1. ,<no space>
2. ,<spaces>
3. , , , , ,
4. <spaces>
5. <spaces>,
6. <spaces>,<spaces>
Solution 5 - Javascript
The greatly upvoted answer removes not only the final comma, but also any spaces that follow. But removing those following spaces was not what was part of the original problem. So:
let str = 'abc,def,ghi, ';
let str2 = str.replace(/,(?=\s*$)/, '');
alert("'" + str2 + "'");
'abc,def,ghi '
Solution 6 - Javascript
long shot here
var sentence="I got,. commas, here,";
var pattern=/,/g;
var currentIndex;
while (pattern.test(sentence)==true) {
currentIndex=pattern.lastIndex;
}
if(currentIndex==sentence.trim().length)
alert(sentence.substring(0,currentIndex-1));
else
alert(sentence);
Solution 7 - Javascript
Remove last comma. Working example
function truncateText() {
var str= document.getElementById('input').value;
str = str.replace(/,\s*$/, "");
console.log(str);
}
<input id="input" value="address line one,"/>
<button onclick="truncateText()">Truncate</button>
Solution 8 - Javascript
you can remove last comma:
var sentence = "I got,. commas, here,";
sentence = sentence.replace(/(.+),$/, '$1');
console.log(sentence);
Solution 9 - Javascript
First, one should check if the last character is a comma. If it exists, remove it.
if (str.indexOf(',', this.length - ','.length) !== -1) {
str = str.substring(0, str.length - 1);
}
NOTE str.indexOf(',', this.length - ','.length) can be simplified to str.indexOf(',', this.length - 1)
Solution 10 - Javascript
The problem is that you remove the last comma in the string, not the comma if it's the last thing in the string. So you should put an if to check if the last char is ',' and change it if it is.
EDIT: Is it really that confusing?
'This, is a random string'
Your code finds the last comma from the string and stores only 'This, ' because, the last comma is after 'This' not at the end of the string.
Solution 11 - Javascript
With or without Regex.
I suggest two processes and also consider removing space as well. Today I got this problem and I fixed this by writing the below code.
I hope this code will help others.
//With the help of Regex
var str = " I am in Pakistan, I am in India, I am in Japan, ";
var newstr = str.replace(/[, ]+$/, "").trim();
console.log(newstr);
//Without Regex
function removeSpaceAndLastComa(str) {
var newstr = str.trim();
var tabId = newstr.split(",");
strAry = [];
tabId.forEach(function(i, e) {
if (i != "") {
strAry.push(i);
}
})
console.log(strAry.join(","));
}
removeSpaceAndLastComa(str);
Solution 12 - Javascript
If you are targeting es6, then you can simply do this
str = Array.from( str ).splice(0, str.length - 1).join('');
-
This
Array.from(str)
converts the string to an array (so we can slice it) -
This
splice( 0 , str.length - 1 )
returns an array with the items from the array sequentially except the last item in the array -
This
join('')
joins the entries in the array to form a string
Then if you want to make sure that a comma actually ends the string before performing the operation, you can do something like this
str = str.endsWith(',') ? Array.from(str).splice(0,str.length - 1).join('') : str;