iterating over DictRow
От | Karsten Hilbert |
---|---|
Тема | iterating over DictRow |
Дата | |
Msg-id | 20200923215444.GA25406@hermes.hilbert.loc обсуждение исходный текст |
Ответы |
Re: iterating over DictRow
RE: iterating over DictRow |
Список | psycopg |
Dear all, I cannot currently wrap my head around why I am seeing this: 2020-09-23 23:30:23 gmConnectionPool.py::<module>() #87): psycopg2 module version: 2.8.5 (dt dec pq3 ext) 2020-09-23 23:30:23 gmConnectionPool.py::<module>() #88): PostgreSQL via DB-API module "<module 'psycopg2' from '/usr/lib/python3/dist-packages/psycopg2/__init__.py'>":API level 2.0, thread safety 2, parameter style "pyformat" 2020-09-23 23:30:23 gmConnectionPool.py::<module>() #89): libpq version (compiled in): 120002 2020-09-23 23:30:23 gmConnectionPool.py::<module>() #90): libpq version (loaded now) : 120004 ... 2020-09-23 23:30:28 gmConnectionPool.py::__log_on_first_contact() #445): heed Prime Directive 2020-09-23 23:30:28 gmConnectionPool.py::__log_on_first_contact() #457): PostgreSQL version (numeric): 11.7 ... 2020-09-23 23:31:02 gmMacro.py::_get_variant_diagnoses() #2442): [[260, 'L: Bewegungsapparat', False, 'B', 'clin.health_issue'],[260, 'K: aHT/HI', False, 'B', 'clin.health_issue'], [260, 'D: Verdauung', False, None, 'clin.health_issue']] 2020-09-23 23:31:02 gmMacro.py::_get_variant_diagnoses() #2443): <class 'psycopg2.extras.DictRow'> 2020-09-23 23:31:02 gmMacro.py::_escape_dict() #2851): 260 2020-09-23 23:31:02 gmMacro.py::__getitem__() #880): placeholder handling error: diagnoses:: \item %(diagnosis)s:: Traceback (most recent call last): File "/home/ncq/Projekte/gm/git/gnumed/gnumed/Gnumed/wxpython/gmMacro.py", line 869, in __getitem__ val = handler(data = options) File "/home/ncq/Projekte/gm/git/gnumed/gnumed/Gnumed/wxpython/gmMacro.py", line 2445, in _get_variant_diagnoses return '\n'.join(template % self._escape_dict(dx, none_string = '?', bool_strings = [_('yes'), _('no')]) for dx inselected) File "/home/ncq/Projekte/gm/git/gnumed/gnumed/Gnumed/wxpython/gmMacro.py", line 2445, in <genexpr> return '\n'.join(template % self._escape_dict(dx, none_string = '?', bool_strings = [_('yes'), _('no')]) for dx inselected) File "/home/ncq/Projekte/gm/git/gnumed/gnumed/Gnumed/wxpython/gmMacro.py", line 2852, in _escape_dict val = the_dict[field] File "/usr/lib/python3/dist-packages/psycopg2/extras.py", line 169, in __getitem__ return super(DictRow, self).__getitem__(x) IndexError: list index out of range This line logs a list of DictRow's: 2020-09-23 23:31:02 gmMacro.py::_get_variant_diagnoses() #2442): [[260, 'L: Bewegungsapparat', False, 'B', 'clin.health_issue'],[260, 'K: aHT/HI', False, 'B', 'clin.health_issue'], [260, 'D: Verdauung', False, None, 'clin.health_issue']] as evidenced here: 2020-09-23 23:31:02 gmMacro.py::_get_variant_diagnoses() #2443): <class 'psycopg2.extras.DictRow'> The logging code: _log.debug('%s', selected) _log.debug('%s', type(selected[0])) and then iterates over the list of DictRow's as per list comprehension like so: return '\n'.join(template % self._escape_dict(dx, none_string = '?', bool_strings = [_('yes'), _('no')]) for dx in selected) where _escape_dict() does this: def _escape_dict(self, the_dict=None, date_format='%Y %b %d %H:%M', none_string='', bool_strings=None): data = {} for field in the_dict: _log.debug('%s', field) val = the_dict[field] if val is None: ... if isinstance(val, bool): ... if isinstance(val, datetime.datetime): ... if self.__esc_style in ['latex', 'tex']: ... elif self.__esc_style in ['xetex', 'xelatex']: ... return data Iterating over the_dict should work for lists (produces values) OR dicts (produces keys, under py3). It seems as if the line for field in the_dict: # I hoped to iterate over the keys = column names somehow "decides": "currently we are treating the_dict as a list (after all, it is a DictRow, which _can_ be treated as a list) which then "turns" the dict-style access in val = the_dict[field] into a list access. Somehow I have a feeling that due to the type of "field" -- it being integer (namely, a primary key) -- forces the_dict[field] to attempt a list-style index based access (which fails, due to there not being 260 columns in the SQL query result :-) Solutions that come to mind: _Must_ I use RealDictCursor() to safely avoid this trap ? (or else dict()ify DictRow's as needed) Any insights to be had ? Thanks, Karsten -- GPG 40BE 5B0E C98E 1713 AFA6 5BC0 3BEA AC80 7D4F C89B
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