Re: [Tutor] The magic parentheses
Sunday, January 24, 2010 9:28 PM
From:
"David Hutto" <dwightdhu...@yahoo.com>
Add sender to Contacts
To:
"Alan Gauld" <alan.ga...@btinternet.com>
--- On Sun, 1/24/10, Alan Gauld <alan.ga...@btinternet.com> wrote:
> From: Alan Gauld <alan.ga...@btinternet.com>
> Subject: Re: [Tutor] The magic parentheses
> To: tutor@python.org
> Date: Sunday, January 24, 2010, 8:06 PM
>
> "Lie Ryan" <lie.1...@gmail.com>
> wrote
> >> and used print, I thought they would be considered
> the same whether as a variable, or as a direct line, guess
> not.
> > what is equivalent:
> > print (a, b, c)
> >
> > and
> > x = a, b, c
> > print x
> >
> > both construct a tuple and prints a,b,c as tuple
>
> Not quite:
>
> >>> a = 1
> >>> b = 2
> >>> c = 3
> >>> x = a,b,c
> >>> print a,b,c
> 1 2 3
> >>> print x
> (1, 2, 3)
> >>>
>
> The first form prints multiple values the second prints the
> repr of a single tuple value. The output is different.
>
> Alan G.
>
So 'print a,b,c' says display the values of a,b,c in the sequence of a,b,c
given. 'print x' says print the value of x, x grabs a's value, b's value, and
c's value, and displays the values for print.
So the sequence becomes a tuple because it's a value of values, and it's sum
comes back in the form of a tuple, not an actual end variable. In other words
the second leap to find the values of a,b,c for value x, makes the result
printed for x(x becomes an array of other data a tuple, correct?
Now if I want to turn the first values listed under x into tuples(or use the
format function that I think was named in another reply to return the non-tuple
version of the value for x and I'm going to try it in a few min) of the other
two variables, like below:
g = f
a = b,c
b = a,c
c = a,g
x = a,b,c
This is off the topic I think, so I'll repost under another if necessary, but
how do I avoid going into the loop of tuples/variables. If a is dependent on
knowing what b,c are, and b is dependent on knowing what a and c are, and c is
dependent on knowing what a and b are, how do I prevent from going into a
defining loop for each.
This is just basically playing with Python's functions, I was just wondering
how to approach such a problem where variables must come in order but might be
dependent on a following variable who's positioning is needed to maintain the
hierarchy of other variables it might represent.
In the above, if I want to know c it requires knowing a,g. But in order to know
a, a needs to know b,c-so I can't list c above a or a above c, because I get
the error that the value of the other is not known when I try to run the script.
David
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
