[Tutor] Long Lines techniques

[Avi Gross]

Steve[n],

Yes, I figured out what the problem was but while evaluating I also realized
that a format string was an ALTERNATIVE that automatically called for an str
or repr so in a sense it would work without debugging. 

I find that sometimes the long lines make it harder to see the skeleton of
the logic as you get bogged down by things that may be of lesser importance.

So I close with another idea. I asked about functions with lots of
arguments. An example might be making a graph using a library that lets you
specify literally hundreds of parameters all at once. I realized that a
perfectly valid alternative to make the main purpose more reasonable would
be to stuff all the extra arguments in a dictionary like

Other_args = { this: value,
		That : value,
		...
		}
That is something in braces that can be wrapped for legibility.

Then the main function call can use the **  expansion like so:

Ret = function(from, to, **Other_args)

Of course, you can also use * with a list or other iterable for the
positional args when that makes it easier but at some point you no longer
have a feel as to what the function call is doing. But hiding less important
details this way seems to be good. Not sure about run-time efficiency, of
course.

-----Original Message-----
From: Tutor <tutor-bounces+avigross=verizon.net at python.org> On Behalf Of
Steven D'Aprano
Sent: Friday, December 14, 2018 12:22 AM
To: tutor at python.org
Subject: Re: [Tutor] Long Lines techniques

On Thu, Dec 13, 2018 at 11:07:59PM -0500, Avi Gross wrote:

[...]
> There are cases where it may make sense to have a long like connected 
> by AND or OR given how python does short-circuiting while returning 
> the last thing or two it touched instead of an actual True/False. For 
> example, you may want to take the first available queue that is not 
> empty with something like
> this:
> 
> Using = A or B or C or ... or Z
> Handling = Using.pop()
> 
> Sure, that could be rewritten into multiple lines. 

using = (A or B
         or C or D 
         or E or F)


[...]
> I recently wrote some code and ran into error messages on lines I was 
> trying to keep short:
> 
> A = 'text"
> A += "more text"
> A += object
> A+= ...

Without knowing the error message, its impossible to say what the problem
is. My guess is that the object on line three wasn't a string. 
In which case, the obvious fix is:

A += str(object)



--
Steve
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