def efloat(x):
    """
    Convert regular floating point stings an those prefixed by 'e',
    where the prefix indicates if the given epoch is estimated. Return
    the float and True or False if estimated. The float string '-' is
    returned as None.
    """
    if x.startswith('e'):
        return float(x[1:]), True
    elif x.strip() == '-':
        return None, False
    else:
        return float(x), False