def is_float(num):
    """
    given a string variable, returns True if the string can be directly converted to a float, otherwise returns False
    :param num: string to check whether or not it can be converted to a float
    :type num: string
    :return: True: the string can be converted to a float (via the float(<string>) function). False: it cannot.
    :rtype: boolean
    """
    try:
        float(num)
        return True
    except ValueError:
        return False