Converting float numbers to binary

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I need to convert a float value to binary. This value can be from 0 to 99.99.

I saw that if the value is an int and between 0 to 255 I just have to do

n = [255]
num = byte(n)

How is not possible directly convert a float to binary (I think), my first step was multiply my float number *100 and have an integer from 0 to 9999.

Now I need 4 bytes to represent the number.

It is possible do something like this arduino code (below)?

n = 9999
byte = pl[4];

pl[0] = (byte) ((n & 0xFF000000) >> 24 );
pl[1] = (byte) ((n & 0x00FF0000) >> 16 );
pl[2] = (byte) ((n & 0x0000FF00) >> 8 );
pl[3] = (byte) ((n & 0X000000FF));

Basically I'm applying a mask, but I don't know how to do it with python because I'm a noob. :/

MORE INFO:

The objective is to reduce the length of my result to send this with a wireless protocol. That's why I'm converting it to byte.

Thank you very much

python
python-3.x
asked on Stack Overflow Dec 7, 2019 by Lleims • edited Dec 7, 2019 by Lleims

3 Answers

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One equivalent would be 

x=2049
p0 = (x>>24)&255
p1 = (x>>16)&255
p2 = (x>>8)&255
p3 = x&255
answered on Stack Overflow Dec 7, 2019 by jeremy_rutman
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Yes you can do exactly the same thing in python.

This would be the literal translation of your code.

n = int(floatnumber * 100 + 0.5)
bytes_to_write = bytes([(n>>24)&255, (n>>16)&255, (n>>8) & 255, n & 255])

However you could also use the struct module ( https://docs.python.org/3.6/library/struct.html ) and ( https://docs.python.org/3.6/library/struct.html#format-characters ) for the format characters:

import struct
n = int(floatnumber * 100 + 0.5)
bytes_to_write = struct.pack(">l", n)

storing the int as big endian byte sequence

For creating only two bytes use

n = int(floatnumber * 100 + 0.5)
bytes_to_write = bytes([(n>>8) & 255, n & 255])

or

import struct
n = int(floatnumber * 100 + 0.5)
bytes_to_write = struct.pack(">H", n)
answered on Stack Overflow Dec 7, 2019 by gelonida • edited Dec 8, 2019 by gelonida
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As per your comments You need this:

number = float(input("Enter any number:"))
decimal = int(str(number).split(".")[0])
print(decimal)
mantissa= int(str(number).split(".")[1])
print(mantissa)
if mantissa != 0:
    pass
else:
    mantissa = 0
int_num = decimal*(10**(len(str(mantissa))))+mantissa

You'll get the integer value of that number without decimal point. Now you can convert that into binary directly.

answered on Stack Overflow Dec 7, 2019 by theashwanisingla

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