[Tutor] How is "set(ls).add('a') evaluated? [Was: Re: A program that can check if all elements of the list are mutually disjoint]

[Marc Tompkins]

On Sun, Jun 6, 2021 at 5:58 PM Richard Damon <Richard at damon-family.org>
wrote:

> It's quite possible that two avenues which are both 'north/south' cross
> at 90 degrees as the north-south rule is likely a 'general' case, while
> at a particular point they may deviate significantly.
>
> In the central San Fernando Valley (inside the city of LA), most
boulevards do run east/west and almost all avenues run north/south - but
several of the major north/south roads (Sepulveda, Balboa, Reseda, Topanga
Canyon) break the rule and are called boulevards. A few miles east in the
city of Burbank, the entire grid is rotated 45 degrees and there are
multiple avenue/avenue and boulevard/boulevard intersections running NW/SE
and NE/SW.
The rule is useful as a guideline, but ONLY if the designers of the system
followed the rule themselves - otherwise it just helps you get lost. (Hence
my parallel to API naming schemes.)



> I have one stretch of road near me that is at the same time a North
> Bound Highway, an East Bound Highway and a South Bound Highway.
>

US 101 (or, in LA-speak, "the 101") is officially a north/south highway -
one of the major north/south arteries of the state - but in the San
Fernando Valley, it runs nearly due east/west. In fact, due to meandering,
there are a few places where you can be northbound on the 101 but actually
driving southwest.