On Fri, 18 Jun 2010 03:54:05 pm Lang Hurst wrote:
> Is there a way to just return the values when using sqlite3?
>
> If I:
>
> names = c.execute('select names from students')
> for name in names: print names
What is c? A Cursor or a Connection object? It probably doesn't make any
real difference, but it could, and so you should say.
> I get the list I want, but they look like
>
> (u'Cleese, John')
> (u'Jones, Terry')
> (u'Gillaim, Terry')
I doubt it. Did you mean this?
(u'Cleese, John',)
Note the comma at the end. A subtle difference, but a HUGE one.
Punctuation is important: it's what makes the difference between:
"Let's eat, Grandma!"
and
"Let's eat Grandma!"
In Python, the comma makes it a tuple, rather than a meaningless pair of
parentheses.
> is there a way to just return
>
> Cleese, John
> Jones, Terry
> Gillaim, Terry
No, because you're not *returning* anything, you're *printing*, and
printing a tuple prints the opening and closing brackets plus the
repr() of each internal object.
Compare the following:
>>> t = (u"Cleese, John",) # a tuple like that returned by execute
>>> print t # print the tuple
(u'Cleese, John',)
>>> print t[0] # print the unicode string alone
Cleese, John
>>> print repr(t[0]) # print the unicode string's repr()
u'Cleese, John'
This is fundamental stuff: objects are not their printable
representation, any more than you are a photo of you.
What is printed is not the same as the object itself. Every object has
its own printable representation. In some cases it looks exactly the
same as the way you enter the object as a literal:
>>> print 42
42
in other cases it is not:
>>> print "Hello world"
Hello world
>>> print repr("Hello world")
'Hello world'
>>> print "Hello world" # includes a tab character
Hello world
>>> print repr("Hello world")
'Hello\tworld'
In this case, the object returned by execute is a list of tuples. If
there is only a single object in each tuple, it is still a tuple, and
it still prints as a tuple. If you want to print something other than a
tuple, don't print the tuple:
names = c.execute('select names from students')
for t in names:
name = t[0] # Extract the first item from each tuple.
print name
Of course you can combine the two lines inside the loop:
print t[0]
> It seems a shame to have to run the answers through a stip process.
It would be more of a shame if execute sometimes returned a list of
tuples, and sometimes a list of other objects, with no easy way before
hand of knowing what it would return.
--
Steven D'Aprano
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