strings (dollar.cents) into floats

[luca bertini]

Hi,

i have strings which look like money values (ie 34.45)
is there a way to convert them into float variables?
everytime i try I get this error: "numb = float(my_line) ValueError:  
empty string for float()"
"
here's the code

************

import sys
import re

for line in sys.stdin.readlines():
	my_line = line.rstrip()
	numb = float(my_line)
	print numb