KeyError: self._index[x]

Sorry, accidentally pressed send.

cur_p = conn_pr(cursor_factory=psycopg2.extras.DictCursor)
cur_t = conn_t.cursor(cursor_factory=psycopg2.extras.DictCursor)

cur_t.execute("""
SELECT TRANSLATE(snumber, ' ', '')
FROM sprofile """)

# This will result in KeyError
for row in cur_t:
print row['snumber']

# This works fine
for row in cur_t:
print row[0]

Sorry again.

I would really appreciate any suggestions.

Thanks,
J

On Monday, May 7, 2018, tango ward <tangoward15@gmail.com> wrote:

cur_t.execute("""
SELECT TRANSLATE(snumber, ' ', '')
FROM sprofile """)

# This will result in KeyError
for row in cur_t:
print row['snumber']

# This works fine
for row in cur_t:
print row[0]

So apparently when you execute your query the result has at least one
column but that column isn't named "snumber". I'm sure there is a way in
Python to debug "row" and find out what names it does have. Or maybe
execute the query in something like psql and observe e column name there.

That said, by default the name of columns whose values are derived by a
single function call should be the name of the function. So "translate",
not "snumber" - the latter being consumed by the function. You can as use
"as <alias>" to give it a different fixed name and refer to that.

David J.

On 05/07/2018 08:50 PM, David G. Johnston wrote:

On Monday, May 7, 2018, tango ward <tangoward15@gmail.com
<mailto:tangoward15@gmail.com>> wrote:

cur_t.execute("""
                SELECT TRANSLATE(snumber, ' ', '')
                FROM sprofile """)

# This will result in KeyError
for row in cur_t:
print row['snumber']

# This works fine
for row in cur_t:
print row[0]

So apparently when you execute your query the result has at least one
column but that column isn't named "snumber".  I'm sure there is a way
in Python to debug "row" and find out what names it does have.  Or maybe

Python 3+
print(row)

Python 2.7
print row

execute the query in something like psql and observe e column name there.

That said, by default the name of columns whose values are derived by a
single function call should be the name of the function.  So
"translate", not "snumber" - the latter being consumed by the function.
You can as use "as <alias>" to give it a different fixed name and refer
to that.

David J.

--
Adrian Klaver
adrian.klaver@aklaver.com

On 05/07/2018 08:11 PM, tango ward wrote:

Sorry, accidentally pressed send.

cur_p = conn_pr(cursor_factory=psycopg2.extras.DictCursor)
cur_t = conn_t.cursor(cursor_factory=psycopg2.extras.DictCursor)

cur_t.execute("""
                SELECT TRANSLATE(snumber, ' ', '')
                FROM sprofile """)

DictCursor is a hybrid dict/sequence.

# This will result in KeyError
for row in cur_t:
print row['snumber']

Above you are using it as a dict and as David pointed you would need to
use translate as the key:

test=> select translate('test', '', '');
translate
-----------
test

# This works fine
for row in cur_t:
print row[0]

Above you are using as a sequence, so the indexing works.

Sorry again.

I would really appreciate any suggestions.

Thanks,
J

--
Adrian Klaver
adrian.klaver@aklaver.com

Shall I loop using the 'translate' as key to my row?

On Tue, May 8, 2018 at 12:10 PM, Adrian Klaver <adrian.klaver@aklaver.com>
wrote:

Yeah you're right, making 'translate' as the key works. Thanks for pointing
this out Sir David "That said, by default the name of columns whose values
are derived by a single function call should be the name of the function."
I didn't know it. Is it only in psycopg2 that the name of the columns will
use the name of the function?

On Tue, May 8, 2018 at 12:40 PM, tango ward <tangoward15@gmail.com> wrote:

On Monday, May 7, 2018, tango ward <tangoward15@gmail.com> wrote:

I didn't know it. Is it only in psycopg2 that the name of the columns
will use the name of the function?

The server assigns column names - hence the advice to use psql to
investigate SQL issues more easily since there is one less moving part to
deal with.

David J.

Thanks, now I understand. Thank you so much for being so helpful to a
newbie same with Sir Adrian.

On Tue, May 8, 2018 at 12:58 PM, David G. Johnston <
david.g.johnston@gmail.com> wrote: