def cif2float(cifnum):
    """
    Convert a cif-floating point number that may include an uncertainty
    indication to a proper floating point number. 
    In a .cif file the value "0.4254(4)" is a floating point number where
    the digit in brackets gives the uncertainty. To convert this number to
    a regular Python floating point number the uncertainty needs to be 
    eliminated and the resulting string converted.
    """
    ii = cifnum.find("(")
    if ii >= 0:
      pnum = float(cifnum[:ii])
    else:
      pnum = float(cifnum)
    return pnum