How do you express binary literals in Python

Question

How do you express an integer as a binary number with Python literals   I was easily able to find the answer for hex    gt  gt  gt  0x12AF 4783  gt  gt  gt  0x100 256   and octal    gt  gt  gt  01267 695  gt  gt  gt  0100 64   How do you use literals to express binary in Python     Summary of Answers   Python 2 5 and earlier  can express binary using int  01010101111  2  but not with a literal  Python 2 5 and earlier  there is no way to express binary literals  Python 2 6 beta  You can do like so  0b1100111 or 0B1100111  Python 2 6 beta  will also allow 0o27 or 0O27  second character is the letter O  to represent an octal  Python 3 0 beta  Same as 2 6  but will no longer allow the older 027 syntax for octals

User · Answer

As far as I can tell Python  up through 2 5  only supports hexadecimal  amp  octal literals   I did find some discussions about adding binary to future versions but nothing definite

User · Answer

For reference mdash future Python possibilities  Starting with Python 2 6 you can express binary literals using the prefix 0b or 0B    gt  gt  gt  0b101111 47   You can also use the new bin function to get the binary representation of a number    gt  gt  gt  bin 173   0b10101101    Development version of the documentation  What s New in Python 2 6

User · Answer

Another good method to get an integer representation from binary is to use eval   Like so  def getInt binNum   0       return eval eval  0b    str n     I guess this is a way to do it too  I hope this is a satisfactory answer  D

User · Answer

gt  gt  gt  print int  01010101111  2  687  gt  gt  gt  print int  11111111  2  255   Another way

User · Answer

I ve tried this in Python 3 6 9 Convert Binary to Decimal  gt  gt  gt  0b101111 47   gt  gt  gt  int  101111  2  47  Convert Decimal to binary  gt  gt  gt  bin 47   0b101111   Place a 0 as the second parameter python assumes it as decimal   gt  gt  gt  int  101111  0  101111

User · Answer

How do you express binary literals in Python    They re not  binary  literals  but rather   integer literals   You can express integer literals with a binary format with a 0 followed by a B or b followed by a series of zeros and ones  for example    gt  gt  gt  0b0010101010 170  gt  gt  gt  0B010101 21   From the Python 3 docs  these are the ways of providing integer literals in Python      Integer literals are described by the following lexical definitions   integer           decinteger   bininteger   octinteger   hexinteger decinteger        nonzerodigit        digit      0           0    bininteger         0    b     B          bindigit   octinteger         0    o     O          octdigit   hexinteger         0    x     X          hexdigit   nonzerodigit       1     9  digit              0     9  bindigit           0     1  octdigit           0     7  hexdigit          digit    a     f     A     F        There is no limit for the length of integer literals apart from what   can be stored in available memory       Note that leading zeros in a non-zero decimal number are not allowed    This is for disambiguation with C-style octal literals  which Python   used before version 3 0       Some examples of integer literals   7     2147483647                        0o177    0b100110111 3     79228162514264337593543950336     0o377    0xdeadbeef       100 000 000 000                   0b 1110 0101       Changed in version 3 6  Underscores are now allowed for grouping purposes in literals    Other ways of expressing binary   You can have the zeros and ones in a string object which can be manipulated  although you should probably just do bitwise operations on the integer in most cases  - just pass int the string of zeros and ones and the base you are converting from  2     gt  gt  gt  int  010101   2  21   You can optionally have the 0b or 0B prefix    gt  gt  gt  int  0b0010101010   2  170   If you pass it 0 as the base  it will assume base 10 if the string doesn t specify with a prefix    gt  gt  gt  int  10101   0  10101  gt  gt  gt  int  0b10101   0  21   Converting from int back to human readable binary   You can pass an integer to bin to see the string representation of a binary literal    gt  gt  gt  bin 21   0b10101    And you can combine bin and int to go back and forth    gt  gt  gt  bin int  010101   2    0b10101    You can use a format specification as well  if you want to have minimum width with preceding zeros    gt  gt  gt  format int  010101   2     fill  width b  format width 10  fill 0    0000010101   gt  gt  gt  format int  010101   2    010b    0000010101

User · Answer

0 in the start here specifies that the base is 8  not 10   which is pretty easy to see     gt  gt  gt  int  010101   0  4161   If you don t start with a 0  then python assumes the number is base 10    gt  gt  gt  int  10101   0  10101

User · Answer

I am pretty sure this is one of the things due to change in Python 3 0 with perhaps bin   to go with hex   and oct     EDIT  lbrandy s answer is correct in all cases

[python] How do you express binary literals in Python?

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