def make_num(str_list):
    """make the elements of string list str_list numerical if possible.
    Otherwise remove initial and trailing spaces.
    """
    res = []
    for e in str_list:
        try:
            res.append(int(e))
        except ValueError:
            try:
                res.append(float(e))
            except ValueError:
                res.append(e.strip())
    return res
