hex -> 16bit signed int (newbie)

[Duncan Booth]

"zif" <zf_acs at DELETETHIShotmail.com> wrote in 
news:TTRma.1502$KH1.321574 at news20.bellglobal.com:

> How can I get 16bit signed int from a hex string?
> Eval('0x...') gives me 16bit unsigned,
> struct.pack('i', '\x..\x..') works fine, but
> Python doesn't allow me to concatenate strings
> with '\' (str(92) gives me '\\', which doesn't
> work as well).
> 
How about this?

>>> def signedFromHex16(s):
	v = int(s, 16)
	if not 0 <= v < 65536:
		raise ValueError, "hex number outside 16 bit range"
	if v >= 32768:
		v = v - 65536
	return v

>>> signedFromHex16("ffff")
-1
>>> signedFromHex16("8000")
-32768
>>> signedFromHex16("7fff")
32767
>>> 

-- 
Duncan Booth                                             duncan at rcp.co.uk
int month(char *p){return(124864/((p[0]+p[1]-p[2]&0x1f)+1)%12)["\5\x8\3"
"\6\7\xb\1\x9\xa\2\0\4"];} // Who said my code was obscure?