Convert Hex String to Integer in Python

Convert hex string to integer in Python

Without the 0x prefix, you need to specify the base explicitly, otherwise there's no way to tell:

x = int("deadbeef", 16)

With the 0x prefix, Python can distinguish hex and decimal automatically:

>>> print(int("0xdeadbeef", 0))
3735928559
>>> print(int("10", 0))
10

(You must specify 0 as the base in order to invoke this prefix-guessing behavior; if you omit the second parameter, int() will assume base-10.)

Convert hex-string to integer with python

Not only that is a string, but it is in little endian order - meanng that just removing the spaces, and using int(xx, 16) call will work. Neither does it have the actual byte values as 4 arbitrary 0-255 numbers (in which case struct.unpack would work).

I think a nice approach is to swap the components back into "human readable" order, and use the int call - thus:

number = int("".join("6c 02 00 00".split()[::-1]), 16)

What happens there: the first part of th expession is the split - it breaks the string at the spaces, and provides a list with four strings, two digits in each. The [::-1] special slice goes next - it means roughly "provide me a subset of elements from the former sequence, starting at the edges, and going back 1 element at a time" - which is a common Python idiom to reverse any sequence.

This reversed sequence is used in the call to "".join(...) - which basically uses the empty string as a concatenator to every element on the sequence - the result of the this call is "0000026c". With this value, we just call Python's int class which accepts a secondary optional paramter denoting the base that should be used to interpret the number denoted in the first argument.

>>> int("".join("6c 02 00 00".split()[::-1]), 16)
620

Another option, is to cummulatively add the conversion of each 2 digits, properly shifted to their weight according to their position - this can also be done in a single expression using reduce, though a 4 line Python for loop would be more readable:

>>> from functools import reduce #not needed in Python2.x
>>> reduce(lambda x, y: x  + (int(y[1], 16)<<(8 * y[0]) ), enumerate("6c 02 00 00".split()), 0)
620

update The OP just said he does not actually have the "spaces" in the string - in that case, one can use just abotu the same methods, but taking each two digits instead of the split() call:

reduce(lambda x, y: x  + (int(y[1], 16)<<(8 * y[0]//2) ), ((i, a[i:i+2]) for i in range(0, len(a), 2)) , 0)

(where a is the variable with your digits, of course) -
Or, convert it to an actual 4 byte number in memory, usign the hex codec, and unpack the number with struct - this may be more semantic correct for your code:

import codecs
import struct
struct.unpack("<I", codecs.decode("6c020000", "hex") )[0]

So the approach here is to pass each 2 digits to an actual byte in memory in a bytes object returned by the codecs.decode call, and struct to read the 4 bytes in the buffer as a single 32bit integer.

Python convert Hex string to Signed Integer

You could do a 64-bit version of this, for example:

def signed_int(h):
    x = int(h, 16)
    if x > 0x7FFFFFFFFFFFFFFF:
        x -= 0x10000000000000000
    return x


print(signed_int('0xb69958096aff3148'))

Output

-5289099489896877752

How to convert hex str into int array

You could range(..) over substrings of length 2:

c = '8db6796fee32785e366f710df10cc' 
c2=[int(c[i:i+2],16) for i in range(0,len(c),2)]

So i iterates of the string with steps of 2 and you take a substring of length 2 from i to i+2 (exclusive) with c[i:i+2]. These you convert by taking int(..,16).

For your sample input it generates:

>>> c='8db6796fee32785e366f710df10cc'
>>> [int(c[i:i+2],16) for i in range(0,len(c),2)]
[141, 182, 121, 111, 238, 50, 120, 94, 54, 111, 113, 13, 241, 12, 12]

The last element is 12 because the length of your string is odd, so it takes c as the last element to parse.

Python: Convert hex string to int and back

def str_to_int(s):
    i = int(s, 16)
    if i >= 2**23:
        i -= 2**24
    return i

def int_to_str(i):
    return '%06x'%((i+2**24)%2**24)

Test results:

In [36]: str_to_int('012345')
Out[36]: 74565

In [37]: str_to_int('fedcba')
Out[37]: -74566

In [38]: int_to_str(74565)
Out[38]: '012345'

In [39]: int_to_str(-74566)
Out[39]: 'fedcba'

Reference: Hex string to signed int in Python 3.2?

How to convert a hex string to an integer?

The value you have is a byte string, not hex. You can encode it to hex then interpret that as a base 16 number. Assuming the return value is meant to be interpreted as one number, and knowing nothing about the format, such as little endian vs big endian, and assuming the \xoo was a typo for \x00.

from binascii import hexlify

data = serial.readline()
hex = hexlify(data)
num = int(hex, 16)

print(num)

How to convert a hex string to hex number

Try this:

hex_str = "0xAD4"
hex_int = int(hex_str, 16)
new_int = hex_int + 0x200
print hex(new_int)

If you don't like the 0x in the beginning, replace the last line with

print hex(new_int)[2:]

Python hexadecimal string to integer conversion error

Python 3 has no limit on it's integer values.

So you can use int(hex_string, 16) to convert even large strings to an integer value.

s = '14fdbc5ade9e3d4097f421fe7b4b54ad05883d589c3b3f6648b5e0ea2b64b359158087b793b859a4c51af0fd8c1edb7a92b8d5843c1a2d659929357c7e1869784435d6dcfd8d29b619194333b38655493eb4eb3deeffbf339e91c7c0f6113b4bb6672f49'

s_int = int(s, 16)

print(s_int)

Result

546755182137531943293891170863886409257177002102958031106970218913938945216495276608761007929774380907079475078176395384371438944791022503587328767282546555465705414556027853888426781796298321719051075009856267471199860627126795651319803721

Convert hex string to usably hex

You have a string in input. You can convert it to an integer using int and a base.

>>> a = "0xbffffe43"
>>> import struct
>>> out = struct.pack("<I",int(a,16))
>>> out
b'C\xfe\xff\xbf'

The b prefix is there because solution was tested with python 3. But it works as python 2 as well.

C is printed like this because python interprets printable characters. But

>>> b'C\xfe\xff\xbf' == b'\x43\xfe\xff\xbf'
True

see:

• Convert hex string to int in Python
• Convert a Python int into a big-endian string of bytes

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