Обсуждение: KeyError: self._index[x]

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]

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

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