In Java how can I get a subsequence of number string whose indices can be as 10^5 digits long

Question

In Java how can I get a subsequence of BigInteger whose indices can be 10^5 digits long.

Example : BigInteger length is 10^5 . I have to find subsequence between index 10^3 and 10^4

Yes , it does not work as substring takes int as arguments , but in my case they are bigIntegers — khetanrajesh, Jul 29 '16 at 22:50
@user2418640 A `String` is backed by a `char[]`, and an array cannot have more than `Integer.MAX_VALUE` elements, so indexes cannot exceed the range of `int`, ergo there is no need for index to be `BigInteger`. — Andreas, Jul 29 '16 at 22:55
@Andreas you are correct . I have update the question . Please check now . — khetanrajesh, Jul 29 '16 at 23:15
A `BigInteger` doesn't have "indices" or "subsequences", so it's unclear what it is you want. Are you saying that if the `BigInteger` has the value `12345678` and you want subsequence between index 1 (inclusive) and index 4 (exclusive), that means a new number with value `567`? or `234`? or what? — Andreas, Jul 29 '16 at 23:42
I like being correct, but since I listed 3 mutually exclusive choices, I still don't know what I was correct about. Update your question and clarify what it is you wanted, e.g. with an example like I gave. — Andreas, Jul 30 '16 at 15:36

Pritam Banerjee · Answer 1 · 2016-07-29T23:22:32.303

1

You can use:

String yourSubstring = Str.substring(9999, 10000);

This is will give you the string from 10^3 to 10^4.

To convert a BigInt to String you can use:

String str = yourBigInt.toString();

edited Jul 29 '16 at 23:22

answered Jul 29 '16 at 23:00

Pritam Banerjee

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Whoever downvoted, can you please add an explanation? – Pritam Banerjee Jul 29 '16 at 23:04
Yup! The endpoint of `Str.substring(begin,end)` is *exclusive*. And FYI, I will remove my DV when you fix your answer. – intboolstring Jul 29 '16 at 23:05
@intboolstring Ok. Got you. Updated the code. I guess this is what he wanted – Pritam Banerjee Jul 29 '16 at 23:13
the index can have 10^3 "digits" not the number 1000 . Also have updated the question based on Andreas comment – khetanrajesh Jul 29 '16 at 23:17
@user2418640 yes, then you convert that number to String and then use the above function – Pritam Banerjee Jul 29 '16 at 23:20
@PritamBanerjee The BigInt can have 10^3 digits means 1000 Digits, so like this: 123123123123....(digit 10^3). – Meik Vtune Jul 30 '16 at 00:20

score 0 · Answer 2 · answered Jul 30 '16 at 08:08

Study this code and see if it solves your question. If it doesn't, maybe you will find some information within that will help.

public class TestBigInteger 
{
    public static void main( String[] args )
    {
        String makeNumber = "";
        int numberOfDigits = 10000;
        String newNumberString = "";
        Random random = new Random();
        BigInteger result;


        for ( int i = 0; i < numberOfDigits; i++ ) {
            makeNumber += random.nextInt( 9 );
        }
        newNumberString = makeNumber.substring( 100, 999);
        result = new BigInteger( newNumberString );

    }

}

In Java how can I get a subsequence of number string whose indices can be as 10^5 digits long

2 Answers2