[Tutor] Declaring variables

[Dimitar Ivanov]

Hello everyone,

I have a (hopefully) quick and easy to explain question. I'm currently
using MySQLdb module to retrieve some information from a database. In my
case, the result that's being yield back is a single line.

As far as my understanding goes, MySQLdb function called 'fetchone()'
returns the result as a tuple. Problem is, the tuple has some unnecessary
characters, such as an additional comma being returned. In my case:

>>>  idquery = 'select id from table;'
>>>  cur = mysql.cursor()
>>>  cur.execute(idquery)
>>>  id = cur.fetchone()
>>>  print id
('idinhere',)

I stumbled across an example given like this:

>>>  (id,) = cur.fetchone()

So I decided to give it a try and the result is exactly what I need:

>>>  (id,) = cur.fetchone()
>>>  print id
idinhere

My question is - can I reliably use this method? Is it always going to
return the string between the brackets as long as I define the variable
with '(,)'? I'm planning to use another query that will be using the result
from this one and then update another database with this result but I must
be sure that the variable will always be the string in and between the
brackets otherwise I'm risking to mess up a lot of things big time.

A backup plan I had was to use the following:

>>>  id = cur.fetchone()
>>>  for x in id:
>>>    id = x

But if the method above is certain to always return only the value I need,
I find it to be a far more elegant solution.

Also, just to clarify things for myself - what does this method of
declaring variables do exactly? I'm sorry if this isn't the right place the
ask and if this has been documented clearly already, I'm not sure what to
use as a search term in order to find an answer.

Thanks a lot in advance! I hope I posted all the details needed and my
question is easy to comprehend.

Regards,
Dimitar