Python exercise 7.2

spam.py

spam = 0.0
Count = 0
fname = raw_input("Enter file name: ")
try:   
	fh = open(fname)
except:
    
	print "File  cannot be opened:",fname
	exit ()
for line in fh:
	if not line.startswith("X-DSPAM-Confidence:") : continue
	spam = spam + float(line[line.find(" ")+1:])
	Count = Count + 1

print "Average spam confidence:",spam / float(Count)