Help on Printing the IDs of a list

[jboy]

Hi,

I have a list consisting of some elements and each element has an Id or a number within it, how can I go about printing those ids in order and to the following format assuming the first element has id of 1, second has id of 2, third has id of 3 and so on and with commas in between each id.

1, 2, 3, ..

I am thinking of the following loop but it doesn't work for me.

while(list.get(1).getId() <= 5)
{System.out.println(list.get(Id - 1).getId());}

Sorry, I have changed my code a bit to make it more understandable. If it doesn't make sense please advise how I should go about this problem based on what I mentioned above.
Thanks.

[RamyaSivakanth]

Hi,
You give the complete piece of code with clear description.Really ,its not understandable.People can't give solutions with assumptions.

-Regards
Ramya

[r035198x]

Just initialize a StringBuilder then do

for(Criminal criminal: criminals) {
       sb.append(criminal.getId()+", ");
}

Then when the loop is done just chop off the extra space comma from the end of the StringBuilder.

[jboy]

Can I just ask what sb and append are and what do they do?
Can't I just go and print the ids of each element?

[r035198x]

sb would be the StringBuilder that I said you should initialize.
The methods for the StringBuilder (including those that delete characters) are well documented in the API specs for that class.

[jboy]

how can i use this object of class to print out the IDs?

[r035198x]

I know that one, it's

System.out.println(sb.toString());

r035198x(<-----rocket scientist

[Tolls]

how can i use this object of class to print out the IDs?

As already suggested, read the API for StringBuilder and it should all come clear.

[jboy]

Thanks everybody, it is working for me now but I need to get rid of the extra comma in the end list. And I don't know how to do it. For example, I need to have 1, 2, 3 and it is showing this as 1, 2, 3,
I am still using the stringbuilder class.

[Fubarable]

The API has a method for that. Again: please read the API first.

[RamyaSivakanth]

to remove the end comma ,use substring method.

gothru this below
substring
public String substring(int start,
int end)Returns a new String that contains a subsequence of characters currently contained in this sequence. The substring begins at the specified start and extends to the character at index end - 1.

Parameters:
start - The beginning index, inclusive.
end - The ending index, exclusive.
Returns:
The new string.
Throws:
StringIndexOutOfBoundsException - if start or end are negative or greater than length(), or start is greater than end.

[r035198x]

to remove the end comma ,use substring method.

...

They are using StringBuilder not string and they don't need substring for that.
Read the other posts already made in this thread so far.

[RamyaSivakanth]

Hello Sir r035198x,

Please gothru the api.

StringBuilder (Java 2 Platform SE 5.0)

-Regards
Ramya

[r035198x]

Hello Sir r035198x,

Please gothru the api.

StringBuilder (Java 2 Platform SE 5.0)

-Regards
Ramya

Why should I go through the API? I know what methods are in there and I wouldn't pick substring for deleting the character at the last position. Better let the OP read the API specs as has already been suggested multiple times rather than trying to spoon feed them.

BTW latest Java version is 1.6 these days.

[RamyaSivakanth]

Thanks everybody, it is working for me now but I need to get rid of the extra comma in the end list. And I don't know how to do it. For example, I need to have 1, 2, 3 and it is showing this as 1, 2, 3,
I am still using the stringbuilder class.

I have given the reply for this..Iam not arguing with you which is latest in java.

[r035198x]

I have given the reply for this..Iam not arguing with you which is latest in java.

Fuburable already answered that question and I had already told the OP the same thing, that they must read the API. There is no need for anyone to copy and paste the contents of the API here.

[jboy]

Thank you for the information, I found the following method and I put it before after the toString method but it didn't delete the last comma and I don't know why.

System.out.println(sb.toString());
sb.deleteCharAt(sb.length() - 1);

Thanks.

[Tolls]

Because you printed out the string first and then removed the comma?

[jboy]

I tried swapping those lines around but still wasn't able to get rid of the comma.

[r035198x]

Verify that the String is indeed at the position that you are passing. Don't you have a space at the end?