Is there an easy way to print byte[] array ( zeros and ones, basically to every bit convert in ascii '1' or ascii '0') to the console ?
4 Answers
You can output the individual bytes by converting their numeric value to base 2. Here are two ways to do it. In both, I will use this byte array:
byte[] array = "HälLø123§$%".getBytes();
Walk the array
for(final byte b : array){
System.out.print(Integer.toString(b & 0xFF /* thx Jason Day */, 2));
}
Output:
10010001100001110100100110110010011001100001110111000110001011001001100110110000101010011110010001001010
Reference:
Use BigInteger
If you want to output the entire array in one piece, use BigInteger:
System.out.println(new BigInteger(array).toString(2));
Output:
100100011000011101001000110110001001100110000111011100000110001001100100011001111000010101001110010010000100101
Reference:
answered Feb 2, 2011 at 13:38
Sean Patrick Floyd
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2 Comments
Jason Day
Careful, neither of these methods take sign extension into account. For example, Integer.toString((byte) 130, 2) results in -1111110, not 10000010. You need to mask off the sign bit first.
Sean Patrick Floyd
@Jason that's true for the first version (and I adjusted it, thanks) but not for the second.
If you want to print the binary representation of each element, you can do something like this:
StringBuilder sb = new StringBuilder();
sb.append("[");
String comma = "";
for (byte b : array) {
int i = b & 0xFF; // cast to int and mask the sign bit
sb.append(comma);
comma = ",";
sb.append(Integer.toBinaryString(i));
}
sb.append("]");
System.out.println(sb.toString());
Comments
You can use commons-codec BinaryCodec:
BinaryCodec.toAsciiString(array)
For better control on the output, you can use toAsciiChars(..) and print the char[].
(If you simply want to output the array values - java.util.Arrays.toString(array));
4 Comments
biziclop
That would display the bytes in decimal though, wouldn't it?
Bozho
@biziclop - no, nothing decimal. it will print the contents of the byte array.
biziclop
Although it wasn't from me, I guess because you failed to answer the question. Which was, how to print the array in binary, not decimal.
Bozho
@biziclop aha, I added an additional option for that.
Note: This outputs individual bytes, not individual bits. But as it may still be useful for someone, I'll let it here.
Here the solution for my understanding of the question:
byte[] data = {0, 1, 0, 1, 1, 0};
StringBuilder sb = new StringBuilder(data.length);
for(byte b : data) {
sb.append(b);
}
System.out.println(sb);
This should output 010110.
Integer.toBinaryString()for bytes. Baffles me why there's no such method in theByteclass, to be honest.