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Re: Help with changes in traceback stack from Python 2.7 to Python 3.x

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On Apr 28, 2014, at 12:36 PM, Ned Batchelder <ned@nedbatchelder.com> wrote:

> On 4/27/14 5:51 PM, Andrew Konstantaras wrote:
>        > I guess I am missing something big as I am looking for a shorthand way
>        > of doing the following:
>        >
>        > dctA = dict(x=x, y=y, ... n=n)
>        >
>
> Yes, your makeDict(x, y) is a shorthand for dict(x=x, y=y), but there
> are many things you can do with dict that you can't do with makeDict.
> What is the makeDict equivalent of:
>
> dict(x=12, y=self.y, z=a+b)
>
> The code you have allows you more compact expression, but it brings
> fragility and surprise.
>
>        > This is, as I understand it a very natural way of using a dictionary.
>        > It seems that this syntax is unnecessarily redundant and hence my goal
>        > of writing something more compact. Perhaps the way I am doing it is a
>        > little unorthodox, but the ultimate use of a dictionary is, as I
>        > understand it, completely in line with how dictionaries were designed to
>        > be used. In my other code, I often use these dictionaries to pass
>        > arguments to functions and return results. It allows me great
>        > flexibility without breaking existing code. I pack a dictionary before
>        > passing and unpack when retrieving.
>
> Perhaps you want to create a class instead? If you find yourself
> passing more than a handful of arguments to a function, and especially
> more than a handful of values returned from a function, then a class
> with methods might be a better way to combine state and behavior.
>
> Also, keep in mind that you can return a tuple from a function if you
> want to return two or three values and assign them to names:
>
> x, y, z = compute_xyz()
>
> You mention unpacking your dictionary after the function call. How do
> you do that? Isn't that a cumbersome and repetitive operation?
One of the reasons I like using the dictionary over the tuple is that if I have a function that grows in functionality (i.e., I decide to return more data for new scenarios), I can just add the new object to the dictionary and I don't have to worry about changing the code every where else that used to call the function. 
 
Actually, that is one of the nice features of using a dictionary, I can check if the key is there and if it is pull it out.  As I was dusting off this old code, I considered trying to implement this functionality through by creating a class.  I never liked going through the stack, it seemed hacky, but I came to love using dictionaries as they have some great built in features. 

Again, thanks for the advice and I will focus on the class implementation.

>
>        >
>        > I will give the locals approach a try, it seems a little more clumsy
>        > than simply passing the variables to the function.
>        >
>        > Thanks again for your input.
>        >
>        > ---Andrew
>
> BTW, it's a little easier to follow the threads of conversation if you
> put your responses after the text you are responding to. This is known
> as bottom-posting, and is preferred to top-posting as you did here.
>
>
> -- 
> Ned Batchelder, http://nedbatchelder.com
>
> -- 
> https://mail.python.org/mailman/listinfo/python-list

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Re: Help with changes in traceback stack from Python 2.7 to Python 3.x Andrew Konstantaras <akonsta@icloud.com> - 2014-04-28 19:50 +0000

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