将十进制数转换为字节大小的 8 位数组

Question

x = 64
var_in_bin_format = bin(64)
print(var_in_bin_format)

#Output
#0b1000000

#Desired Output -- > should always be in 8 bit format
#0b01000000

def call_another_api(var_in_bin_format):
    pass

In Python, I need to call an API that expects its parameter to be always in 8 bit format regardless of the value of the decimal number?

I am not that good in bit manipulation so I am thinking if there is something I can do here?

How can I do this? I cannot use the format() function as it will convert the value into a string representation and the API that I am calling will alert me that it is not in the correct format.

Answer 1

Even though you say that you can't use format() because it returns a string, I'm going to post this because that's also what bin() does. bin(x) is equivalent to format(x, '#b') . I'd guess that you haven't added the '#' , which means you won't have '0b' leading the value.

The Python 3 documentation for bin() actually gives a pretty strong hint about how you might do this, using format instead.

If you know that the value passed will not be negative, you can use the format string '#010b' :

format(x, '#010b')

Breaking this down:

• 'b' means that the number will be a string binary representation.
• '10' means that the entire string will be 10 characters long, two for '0b' and 8 for the value.
• '0' makes it pad with '0' instead of ' ' .
• '#' will add the '0b' prefix, as done by bin() .

Note that this assumes that the number is an integer in the range [0, 255]. Integers outside this range will generate valid representations, but will not match the format expected, and may have a leading '-' . Objects of type float can not be converted with the 'b' format code. I assume that these are not problems, given what your intended output is, but it might be a good idea to add an explicit check to throw a ValueError if the value is less than 0 or greater than 255.

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If you're in Python 3.6+, you could also use f-strings:

f'{x:#010b}'

Answer 2

Is is not possible to convert all decimal numbers to 8 bit. You can only convert numbers from 0 to 255 in 8 bits.