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Newbie Question: Obtain element from list of tuples

Chris Angelico rosuav at gmail.com
Sun Dec 18 15:51:08 EST 2011 
On Mon, Dec 19, 2011 at 6:41 AM, HoneyMonster <someone at someplace.invalid> wrote:
> My question is doubtless a very easy one to answer: Say I want the ninth
> element in the twentieth tuple put into variable PID, I can do this,
> bearing in mind that numbering starts at zero:
>
> tup = recs[19]
> PID = tup[8]
>
> But there must be an easier way; i.e. to do it in one go without the
> extra variable. How do I achieve that please?

The specific answer has already been given, but I'd like to fill in
the generality. In Python, everything's an object; if you can do
something with a variable, you can do it with an expression too. I
don't know what your function call is to obtain your record list, but
imagine it's:

recs = conn.query("SELECT * FROM some_table")

Then you can actually do all of this in a single statement. It's not
usually what you'll want to do, but this is legal:

pid = conn.query("SELECT * FROM some_table")[19][8]

If you're absolutely certain that you'll always get precisely one
value from a query, this becomes rather more useful:

mode = conn.query("SELECT mode FROM config WHERE id=5")[0][0]

In any case: You can work with a function's return value directly,
without first storing it in a temporary variable.

Hope that helps!

Chris Angelico
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