floating point - Converting a float in chars to float (PYTHON) -

i have program in python in want receive frame values. values sent xbee.

xbee send float splitted in 4 bytes union struct, this:

typedef union _data{     float f;     char s[4]; } myfloat; 

so example, 17.23 gives me 10, -41, -119, 65. so, have recover these values in python , after got 4, convert them float. have since read each 1 (serial.read()) float resultant?

those values received python script , want join them again float. read struct in python not skill in python , don't understand how works.

i read bytes 1 one using serial.read.

any idea?

if understand correctly, you're getting 4 integers [10, -41, -119, 65] , want reassemble original float. if so, answer contained in @dsm's comments. piecing bits together:

>>> import struct >>> x = [10, -41, -119, 65] >>> struct.unpack('<f', struct.pack('4b', *x))[0] 17.229999542236328 

note we're not getting exactly 17.23 here, because number isn't representable single-precision ieee 754 binary float.

this sounds little topsy-turvy, though: should easier original bytes 4 integers. how getting integer values? if you're using pyserial, couldn't read(4) 4 bytes @ once , use struct.unpack directly on result of that? e.g., i'd expect work (simulated interpreter session):

>>> import struct >>> x_bytes = ser.read(4)  # (where ser serial instance) >>> x = struct.unpack('<f', x_bytes)[0] >>> x 17.229999542236328