Function is_valid_nc3_name

xarray/backends/netcdf3.py:142–170

Test whether an object can be validly converted to a netCDF-3 dimension, variable or attribute name Earlier versions of the netCDF C-library reference implementation enforced a more restricted set of characters in creating new names, but permitted reading names containing arbitrary

(s)

def is_valid_nc3_name(s):
    """Test whether an object can be validly converted to a netCDF-3
    dimension, variable or attribute name

    Earlier versions of the netCDF C-library reference implementation
    enforced a more restricted set of characters in creating new names,
    but permitted reading names containing arbitrary bytes. This
    specification extends the permitted characters in names to include
    multi-byte UTF-8 encoded Unicode and additional printing characters
    from the US-ASCII alphabet. The first character of a name must be
    alphanumeric, a multi-byte UTF-8 character, or '_' (reserved for
    special names with meaning to implementations, such as the
    "_FillValue" attribute). Subsequent characters may also include
    printing special characters, except for '/' which is not allowed in
    names. Names that have trailing space characters are also not
    permitted.
    """
    if not isinstance(s, str):
        return False
    num_bytes = len(s.encode("utf-8"))
    return (
        (unicodedata.normalize("NFC", s) == s)
        and (s not in _reserved_names)
        and (num_bytes >= 0)
        and ("/" not in s)
        and (s[-1] != " ")
        and (_isalnumMUTF8(s[0]) or (s[0] == "_"))
        and all(_isalnumMUTF8(c) or c in _specialchars for c in s)
    )