[英]Converting hexstr to signed integer - Python
I have this hexstr 0xfffffffffffffffffffffffffffffffffffffffffffffffffffdf05d84162877
, in decimal terms it should give -580140491462537
.我有这个 hexstr
0xfffffffffffffffffffffffffffffffffffffffffffffffffffdf05d84162877
,以十进制表示它应该给出-580140491462537
。 However doing the below leads to bad answers.但是,执行以下操作会导致错误的答案。 Can someone help?
有人可以帮忙吗?
In: test = '0xfffffffffffffffffffffffffffffffffffffffffffffffffffdf05d84162877'
In: int(test,16)
Out: 11579208923731619542357098500868790785326998466564056403945758342777263817739
First convert the string to bytes.首先将字符串转换为字节。 You'll have to remove the leading "0x".
您必须删除前导“0x”。 Then use int.from_bytes and specify that it's signed and big-endian.
然后使用 int.from_bytes 并指定它是有符号的和大端的。
In: int.from_bytes(bytes.fromhex(test[2:]), byteorder="big", signed=True)
Out: -580140491462537
I've adapted this answer我已经改编了这个答案
# hex string to signed integer
def htosi(val):
uintval = int(val, 16)
bits = 4 * len(val)
indicative_binary = 2 ** (bits)
indicative_binary_1 = 2 ** (bits-1)
if uintval >= indicative_binary_1:
uintval = int(0 - (indicative_binary - uintval))
return uintval
This does require a pure hex string:这确实需要一个纯十六进制字符串:
test1 = 'fffffffffffffffffffffffffffffffffffffffffffffffffffdf05d84162877'
print(htosi(test1))
-580140491462537
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