从字符串末尾删除逗号或分号（如果存在） - 使用javascript

Question

I am getting a comma seperated or semicolon seperated string. I want to remove the comma or the semicolon which may occur at the end of the string.

I want a javascript or regex expression which removes the comma ( , ) or the semi colon ( ; ) only if it occurs otherwise the string should be left as it is.

please help

Answer 1

Solution

This can be solved simply with regex ^{MDN DOCs} and .replace() ^{MDN DOCs} :

your_string = your_string.replace(/[,;]$/,'');

Here is a jsfiddle that you can run to demo the code: http://jsfiddle.net/5eksE/1/

What's happening

/[,;]$/ is the regex portion of this script. The slashes can be ignored as they are just regex delimiters.

[] is a container for a range of values that you would like to match in this case ,; .

$ indicates the end of the string.

So putting it all together we are hunting for the comma or semi-colon that is right at the end of a string.

Answer 2

正则表达式处理逗号和分号

your_string = your_string.replace(/[,;]$/, "");

Answer 3

You can check where a character occurs in a string using indexOf() and lastIndexOf() . In your case, when lastIndexOf() returns an index that is equal to the length of string minus 1, then the index is for the last character in the string:

var index = input.lastIndexOf(";");
if(index == input.length - 1) 
{
  input = input.substring(0, input.length - 1);
}

Or, as a one liner:

input = input.lastIndexOf(";") == input.length - 1 ?  input.substring(0, input.length -1 ) : input;

Answer 4

treffynnon's answer is correct. To elaborate a little, it just checks whether your string matches the regular expression ,$ (where $ indicates the end of the string), and if so, replaces the comma with an empty string. If you wanted to check for either a comma or a semicolon, you would just change it to

your_string = your_string.replace(/[,;]$/,'');

Answer 5

I normally do

value = value.substring(0, value.length-1)

although I ensure that it is there in my previous loop. Sorry missed the second part of your question. You could put in a ternery

value = value.substring(0, (value[value.length-1] == ',') ? value.length -1 : value.length);

although it is not that elegant.