best way to remove the last comma

[Celinio Fernandes]

Hi,
what is the best way to remove the last comma in my String ?

for (int i=0;i<5,i++)
{
// some pre-treatment here

String foo = "hello";
String result += foo + ", ";

// and some post-treatment here

}

result = hello, hello, hello, hello, hello,
but I want it to be:
result = hello, hello, hello, hello, hello
(without the last comma)

Thanks

[Joanne Neal]

Originally posted by Max longbeach:
Hi,
what is the best way to remove the last comma in my String ?

for (int i=0;i<5,i++)
{
// some pre-treatment here

String foo = "hello";
String result += foo + ", ";

// and some post-treatment here

}

result = hello, hello, hello, hello, hello,
but I want it to be:
result = hello, hello, hello, hello, hello
(without the last comma)

Thanks

String result = "";
String foo = "hello";
for (int i=0;i<5,i++)
{
  // some pre-treatment here
 
  if (i == 0) 
      result += foo;
  else
      result += ", " + foo;
 
  // and some post-treatment here
 
}

[Stuart Gray]

String str = "hello, hello, hello, hello,";
int idx = str.lastIndexOf(",");
if (idx>=0) {
   str = str.substring(0, idx) + str.substring(idx+1);
}

[Joel McNary]

Indeed, the best way to remove it is to not put it in in the first place. But if you need to remove it, you can say:

result = result.substring(0, result.length()-1);

This will chomp the last character in the string.

[Steve Morrow]

I'd also recommend using a StringBuffer/StringBuilder if you're going to be repeatedly concatenating a string...

[Stan James]

Look at String.endsWith() too. You might want to check to see if the comma is there before you remove it.

Let's look into never adding the extra comma. I see this kind of thing often when building delimited lists like yours:

needsComma = false
output = ""
for each word in a list
   if needsComma
      add ", " to output
   add word to output
   needsComma = true
next

I prefer to shortcut a bit:

delimiter = ""
output = ""
for each word in a list
   add delimiter to list
   add word to list
   delimiter = ", "
next

If you can modify the code that generated the list, see if that helps.

[Layne Lund]

My preference is a slight variation of Joanne's suggestion:

String foo = "hello";
[B]String result = foo;[/B]
for (int i = [B]1[/B]; i < 5; i++) {
  // some pre-treatment here
  result += ", " + foo;
  // and some post-treatment here
}

[ August 12, 2005: Message edited by: Layne Lund ]
[ August 12, 2005: Message edited by: Layne Lund ]

[Stan James]

The old "priming the pump" option. One line of code before the loop eliminates a redundant assignment statement every time through the loop. I like that, too.