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I use python 2.6
>>> hex(-199703103) '-0xbe73a3f' >>> hex(199703103) '0xbe73a3f' Positive and negative value are the same?
When I use calc, the value is FFFFFFFFF418C5C1.
735
The hexadecimal value of a negative decimal number can be obtained starting from the binary value of that decimal number positive value. The binary value needs to be negated and then, to add 1. The result (converted to hex) represents the hex value of the respective negative decimal number.
hex() function is one of the built-in functions in Python3, which is used to convert an integer number into it's corresponding hexadecimal form. Syntax : hex(x) Parameters : x - an integer number (int object) Returns : Returns hexadecimal string.
In Python, positive numbers can be changed to negative numbers with the help of the in-built method provided in the Python library called abs (). When abs () is used, it converts negative numbers to positive. However, when -abs () is used, then a positive number can be changed to a negative number.
All the negative and positive numbers along with 0 comprise integers. Thus, the numbers that are greater than 0 are positive, whole numbers lesser than 0 are referred to as negative. This is the concept used in Python is negative program.
Python's integers can grow arbitrarily large. In order to compute the raw two's-complement the way you want it, you would need to specify the desired bit width. Your example shows -199703103 in 64-bit two's complement, but it just as well could have been 32-bit or 128-bit, resulting in a different number of 0xf's at the start.
hex() doesn't do that. I suggest the following as an alternative:
def tohex(val, nbits): return hex((val + (1 << nbits)) % (1 << nbits)) print tohex(-199703103, 64) print tohex(199703103, 64) This prints out:
0xfffffffff418c5c1L 0xbe73a3fL If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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