如何在Python中将以下十六进制字符串转换为float(单精度32位)?
"41973333" -> 1.88999996185302734375E1
"41995C29" -> 1.91700000762939453125E1
"470FC614" -> 3.6806078125E4
方法一
>>> import struct
>>> struct.unpack('!f', '41973333'.decode('hex'))[0]
18.899999618530273
>>> struct.unpack('!f', '41995C29'.decode('hex'))[0]
19.170000076293945
>>> struct.unpack('!f', '470FC614'.decode('hex'))[0]
36806.078125
方法二
from ctypes import *
def convert(s):
i = int(s, 16) # convert from hex to a Python int
cp = pointer(c_int(i)) # make this into a c integer
fp = cast(cp, POINTER(c_float)) # cast the int pointer to a float pointer
return fp.contents.value # dereference the pointer, get the float
print convert("41973333") # returns 1.88999996185302734375E1
print convert("41995C29") # returns 1.91700000762939453125E1
print convert("470FC614") # returns 3.6806078125E4
方法三
import struct
testcases = {
"41973333": 1.88999996185302734375E1,
"41995C29": 1.91700000762939453125E1,
"470FC614": 3.6806078125E4,
}
def hex2float(s):
bins = ''.join(chr(int(s[x:x+2], 16)) for x in range(0, len(s), 2))
return struct.unpack('>f', bins)[0]
for s in testcases:
print(hex2float(s), testcases[s])
#18.8999996185 18.8999996185
#19.1700000763 19.1700000763
#36806.078125 36806.078125
合集
import struct
import ctypes
def f2h(s):
fp = ctypes.pointer(ctypes.c_double(s))
cp = ctypes.cast(fp, ctypes.POINTER(ctypes.c_longlong))
return hex(cp.contents.value)
def float_to_hex(f):
return hex(struct.unpack('<I', struct.pack('<f', f))[0])
def float2hex(s):
fp = ctypes.pointer(ctypes.c_float(s))
cp = ctypes.cast(fp,ctypes.POINTER(ctypes.c_long))
return hex(cp.contents.value)
def h2f(s):
cp = ctypes.pointer(ctypes.c_longlong(s))
fp = ctypes.cast(cp, ctypes.POINTER(ctypes.c_double))
return fp.contents.value
def hex_to_float(h):
i = int(h,16)
return struct.unpack('<f',struct.pack('<I', i))[0]
def hex2float(h):
i = int(h,16)
cp = ctypes.pointer(ctypes.c_int(i))
fp = ctypes.cast(cp,ctypes.POINTER(ctypes.c_float))
return fp.contents.value
if __name__ == '__main__':
f = [1.5,-1.5,3.5,-3.5]
h = []
for i in f:
print(f2h(i)," | ",float_to_hex(i)," | ",float2hex(i))
h.append(float_to_hex(i))
print(h)
for i in h :
print(h2f(i)," | ",hex_to_float(i)," | ",hex2float(i))
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