change the place of elements of binary value

Question

I have a String which contains a binary value ( 101101 ). now I want to check if the last letter is 1 and if so change it to 0 . how can I do that ?

What have you already tried, and in what way is this "changing the order" as per your title? — Jon Skeet, Aug 15 '12 at 12:16
From what you describe, how is this any different from [this question](http://stackoverflow.com/questions/1660034/replace-last-part-of-string)? — thegrinner, Aug 15 '12 at 12:18

score 6 · Accepted Answer · answered Aug 15 '12 at 12:18

6

String result = "101101".substring(0,5) + "0";

why checking? The last character will always be 0, regardless if it was 1 or 0 before...

answered Aug 15 '12 at 12:18

Andreas Dolk

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@matarsak Now what do you mean with *how can I remove it*? – maba Aug 15 '12 at 13:09

Peter Lawrey · Answer 2 · 2012-08-15T12:31:30.453

3

You can write

int i = 0b101101;
if (i & 1 != 0)
   i = i & ~1;

or much simpler

i &= ~1; // sets lowest bit to 0.

edited Aug 15 '12 at 12:31

answered Aug 15 '12 at 12:17

Peter Lawrey

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You could also use `i ^= 1`, assuming you keep the `i & 1 != 0` test. – João Silva Aug 15 '12 at 12:24
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I think your post is kind of misleading since it looks like you're trying to use the hex literal as a binary literal. – DaoWen Aug 15 '12 at 12:24
@João Correct, but with `&=` you don't need the test. – Peter Lawrey Aug 15 '12 at 12:32
@DaoWen A binary literal is what I intended. Thank you. – Peter Lawrey Aug 15 '12 at 12:32
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Unfortunately, this doesn't help the O.P. with the `String` he has at the moment. Maybe put this in there before your code: `String s = ; int i = Integer.parseInt(s);` and this after your code: `s = Integer.toString(i);` – Zéychin Aug 15 '12 at 12:35

score 3 · Answer 3 · answered Aug 15 '12 at 12:19

3

Simple version;

String binary = "101101";

binary = binary.substring(0, binary.length() - 1) + "0";

Example here.

answered Aug 15 '12 at 12:19

Joachim Isaksson

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score 1 · Answer 4 · answered Aug 15 '12 at 12:16

1

One possible solution:

    String k = "101101";

    System.out.println(k);

    int len = k.length();
    char[] charr = k.toCharArray();
    if(charr[len - 1] == '1') {
        charr[len - 1] = '0';
    }
    k = new String(charr);

    System.out.println(k);

answered Aug 15 '12 at 12:16

Less

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You can remove the if statement. The last digit will always be `0`. – Zéychin Aug 15 '12 at 12:38
If you keep removing bits you have Andreas_D's solution. ;) – Peter Lawrey Aug 15 '12 at 12:40
2

yeah, I also forgot to mention - beside being one possible, this is probably the worst solution to this problem... ever :) – Less Aug 15 '12 at 12:43
that was the first post that I saw , now how can I remove the last character ? – Aida E Aug 15 '12 at 12:56
@matarsak Why do you want to remove the last character? Everyone has answered your initial question. Are you suggesting that you want something else now? – maba Aug 15 '12 at 13:10

score 1 · Answer 5 · answered Aug 15 '12 at 12:16

1

int binary = 0b101101;

if ( binary % 2 != 0 )
{
    binary = binary ^ 1b;
}

answered Aug 15 '12 at 12:16

DavidS

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change the place of elements of binary value

5 Answers5