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How can I send a hex number and later do the necessary processing?

I am using Python 3.6.8 and the Eclipse IDE. I'm trying to rearrange the hex value. My code snippet is as follows:
def RearrangeData(Data, dataType):
Data= Data[6:] + Data[4:6] + Data[2:4] + Data[0:2]
return data
I'm calling this function as
#xxxxxxxx is a jumbled hex value and it is of type Float
RearrangeData(xxxxxxxx, Float)
In 3.6.8, the interpreter takes the input as int and not as a string. How can this be fixed? Using what attribute can I decode a hex value for example(0x3F800000) to its IEEE-754 equivalent value? In Python 2.7.5, I could use RearragedData.decode('hex'). What can I use in Python 3.6.8?

If you have a string with hexadecimal digits representing a floating point number in big-endian format, use a combination of struct and codecs to first unhexlify the hex string to binary, then unpack it into a float.
>>> import struct, codecs
>>> struct.unpack('>f', codecs.decode('3FA66666', 'hex'))
(1.2999999523162842,)
If you have an integer, 0x3FA66666 (i.e. 1067869798 in decimal), you can call hex() on it, strip the 0x prefix and do the above:
>>> v = 0x3FA66666
1067869798
>>> v_hex = hex(v)[2:]
'3fa66666'
>>> struct.unpack('>f', codecs.decode(v_hex, 'hex'))
(1.2999999523162842,)

How do I convert a string into big5 encoded characters in Python? [duplicate]

I have a long Hex string that represents a series of values of different types. I need to convert this Hex String into bytes or bytearray so that I can extract each value from the raw data. How can I do this?
For example, the string "ab" should convert to the bytes b"\xab" or equivalent byte array. Longer example:
>>> # what to use in place of `convert` here?
>>> convert("8e71c61de6a2321336184f813379ec6bf4a3fb79e63cd12b")
b'\x8eq\xc6\x1d\xe6\xa22\x136\x18O\x813y\xeck\xf4\xa3\xfby\xe6<\xd1+'

Suppose your hex string is something like
>>> hex_string = "deadbeef"
Convert it to a bytearray (Python 3 and 2.7):
>>> bytearray.fromhex(hex_string)
bytearray(b'\xde\xad\xbe\xef')
Convert it to a bytes object (Python 3):
>>> bytes.fromhex(hex_string)
b'\xde\xad\xbe\xef'
Note that bytes is an immutable version of bytearray.
Convert it to a string (Python ≤ 2.7):
>>> hex_data = hex_string.decode("hex")
>>> hex_data
"\xde\xad\xbe\xef"

There is a built-in function in bytearray that does what you intend.
bytearray.fromhex("de ad be ef 00")
It returns a bytearray and it reads hex strings with or without space separator.

provided I understood correctly, you should look for binascii.unhexlify
import binascii
a='45222e'
s=binascii.unhexlify(a)
b=[ord(x) for x in s]

Assuming you have a byte string like so
"\x12\x45\x00\xAB"
and you know the amount of bytes and their type you can also use this approach
import struct
bytes = '\x12\x45\x00\xAB'
val = struct.unpack('<BBH', bytes)
#val = (18, 69, 43776)
As I specified little endian (using the '<' char) at the start of the format string the function returned the decimal equivalent.
0x12 = 18
0x45 = 69
0xAB00 = 43776
B is equal to one byte (8 bit) unsigned
H is equal to two bytes (16 bit) unsigned
More available characters and byte sizes can be found here
The advantages are..
You can specify more than one byte and the endian of the values
Disadvantages..
You really need to know the type and length of data your dealing with

You can use the Codecs module in the Python Standard Library, i.e.
import codecs
codecs.decode(hexstring, 'hex_codec')

You should be able to build a string holding the binary data using something like:
data = "fef0babe"
bits = ""
for x in xrange(0, len(data), 2)
bits += chr(int(data[x:x+2], 16))
This is probably not the fastest way (many string appends), but quite simple using only core Python.

A good one liner is:
byte_list = map(ord, hex_string)
This will iterate over each char in the string and run it through the ord() function. Only tested on python 2.6, not too sure about 3.0+.
-Josh

Python send hex data via serial port [duplicate]

I have a long Hex string that represents a series of values of different types. I need to convert this Hex String into bytes or bytearray so that I can extract each value from the raw data. How can I do this?
For example, the string "ab" should convert to the bytes b"\xab" or equivalent byte array. Longer example:
>>> # what to use in place of `convert` here?
>>> convert("8e71c61de6a2321336184f813379ec6bf4a3fb79e63cd12b")
b'\x8eq\xc6\x1d\xe6\xa22\x136\x18O\x813y\xeck\xf4\xa3\xfby\xe6<\xd1+'

Suppose your hex string is something like
>>> hex_string = "deadbeef"
Convert it to a bytearray (Python 3 and 2.7):
>>> bytearray.fromhex(hex_string)
bytearray(b'\xde\xad\xbe\xef')
Convert it to a bytes object (Python 3):
>>> bytes.fromhex(hex_string)
b'\xde\xad\xbe\xef'
Note that bytes is an immutable version of bytearray.
Convert it to a string (Python ≤ 2.7):
>>> hex_data = hex_string.decode("hex")
>>> hex_data
"\xde\xad\xbe\xef"

There is a built-in function in bytearray that does what you intend.
bytearray.fromhex("de ad be ef 00")
It returns a bytearray and it reads hex strings with or without space separator.

provided I understood correctly, you should look for binascii.unhexlify
import binascii
a='45222e'
s=binascii.unhexlify(a)
b=[ord(x) for x in s]

Assuming you have a byte string like so
"\x12\x45\x00\xAB"
and you know the amount of bytes and their type you can also use this approach
import struct
bytes = '\x12\x45\x00\xAB'
val = struct.unpack('<BBH', bytes)
#val = (18, 69, 43776)
As I specified little endian (using the '<' char) at the start of the format string the function returned the decimal equivalent.
0x12 = 18
0x45 = 69
0xAB00 = 43776
B is equal to one byte (8 bit) unsigned
H is equal to two bytes (16 bit) unsigned
More available characters and byte sizes can be found here
The advantages are..
You can specify more than one byte and the endian of the values
Disadvantages..
You really need to know the type and length of data your dealing with

You can use the Codecs module in the Python Standard Library, i.e.
import codecs
codecs.decode(hexstring, 'hex_codec')

You should be able to build a string holding the binary data using something like:
data = "fef0babe"
bits = ""
for x in xrange(0, len(data), 2)
bits += chr(int(data[x:x+2], 16))
This is probably not the fastest way (many string appends), but quite simple using only core Python.

A good one liner is:
byte_list = map(ord, hex_string)
This will iterate over each char in the string and run it through the ord() function. Only tested on python 2.6, not too sure about 3.0+.
-Josh

Python3 editing hex string

I'm trying to write a file's hex size in the header of another file. When I convert the length to hex I get b'\x00\x00\x00\x04' so it writes "00000004" to the file.
The file's length is stored in 2 byte intervals though, so I need it to format the string to this b'\x00\x04'. what the easiest way to do this?
import mmap
def compact_bytes(values):
return (values[0] << 4)| values[2]
I tried this but I know it's not correct and not the proper method.

You are converting a number into bytes, not hex. Use the struct module to do this:
struct.pack('>H', values)
This produces an unsigned short, 2 bytes, in big endian order; for the length 4 that'd produce \x00\x04:
>>> import struct
>>> struct.pack('>H', 4)
b'\x00\x04'

Assuming the integer is an big endian unsigned short, use struct.pack with the big endian flag.
struct.pack('>H', values)
In this format string, > is the big endian flag, and H is unsigned short.
Example:
>>> import struct
>>> struct.pack('>H', 4)
b'\x00\x04'
You can find all the struct format characters here.

>>> 4 .to_bytes(2, 'big')
b'\x00\x04'

Convert int to single byte in a string?

I'm implementing PKCS#7 padding right now in Python and need to pad chunks of my file in order to amount to a number divisible by sixteen. I've been recommended to use the following method to append these bytes:
input_chunk += '\x00'*(-len(input_chunk)%16)
What I need to do is the following:
input_chunk_remainder = len(input_chunk) % 16
input_chunk += input_chunk_remainder * input_chunk_remainder
Obviously, the second line above is wrong; I need to convert the first input_chunk_remainder to a single byte string. How can I do this in Python?

In Python 3, you can create bytes of a given numeric value with the bytes() type; you can pass in a list of integers (between 0 and 255):
>>> bytes([5])
b'\x05'
bytes([5] * 5)
b'\x05\x05\x05\x05\x05'
An alternative method is to use an array.array() with the right number of integers:
>>> import array
>>> array.array('B', 5*[5]).tobytes()
b'\x05\x05\x05\x05\x05'
or use the struct.pack() function to pack your integers into bytes:
>>> import struct
>>> struct.pack('{}B'.format(5), *(5 * [5]))
b'\x05\x05\x05\x05\x05'
There may be more ways.. :-)
In Python 2 (ancient now), you can do the same by using the chr() function:
>>> chr(5)
'\x05'
>>> chr(5) * 5
'\x05\x05\x05\x05\x05'

In Python3, the bytes built-in accepts a sequence of integers. So for just one integer:
>>> bytes([5])
b'\x05'
Of course, thats bytes, not a string. But in Python3 world, OP would probably use bytes for the app he described, anyway.