Re: How to turn a defaultdict into a normal dict.
On Wed, 10 Jun 2020 at 23:02, Peter Otten <__pete...@web.de> wrote:
> > However later when I actually use it, accessing a key that is not
> > present, should raise KeyError.
> >
> > Is that somehow possible?
>
> It never occured to me to try that, but:
>
> >>> from collections import defaultdict
> >>> d = defaultdict(list)
> >>> d["x"]
> []
> >>> d.default_factory = None
> >>> d["y"]
> Traceback (most recent call last):
> File "", line 1, in
> KeyError: 'y'
An alternative approach to this would be to use a regular dict from the start...
d.setdefault("x", []).append("stuff")
--
Matt Wheeler
http://funkyh.at
--
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Python Curses Programming HowTo -reviewers?
While studying the curses module I was struck by the paucity of tutorial documentation for the Python version. Fortunately I know C and used to write curses applications back in the 80s/90s so I turned to the C tutorials. However, there are quite a lot of differences between the Python wrapper implementation and the C library. I therefore took it on myself to do a translation of the Linux Documentation Project's "Curses HowTo" by Pradeep Padala into Python. It is mostly a translation of the code with minimal changes to the explanatory text (deleting the stuff about how to compile etc plus some libraries that are not available in Python). I have added a few short sections that the C version does not cover but I thought were useful. This is now available as a PDF and I'd be interested in review comments. Ideally I'm looking for new curses users to review it as a tutorial and for experienced curses users to check that what I've done is sane! It is about 75 pages long and covers the core curses module, the panel module and the textpad widget as well as a brief intro to the dialog module. If anyone feels keen please reply and I'll forward a copy. Eventually I'm aiming to put the finished document on my website. It's amazing what a pandemic can produce... -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos -- https://mail.python.org/mailman/listinfo/python-list
Re: Python Curses Programming HowTo -reviewers?
> If anyone feels keen please reply and I'll forward a copy. I'm interested please forward me a copy. Bob Gailer -- https://mail.python.org/mailman/listinfo/python-list
Aw: Python Curses Programming HowTo -reviewers?
> I therefore took it on myself to do a translation of the Linux > Documentation Project's "Curses HowTo" by Pradeep Padala into Python. > > This is now available as a PDF and I'd be interested in review comments. I'd be interested in having a look, generally. Will this be available somewhere ? Thanks, Karsten -- https://mail.python.org/mailman/listinfo/python-list
Re: Python Curses Programming HowTo -reviewers?
> On Jun 16, 2020, at 11:12 AM, Alan Gauld via Python-list > wrote: > > If anyone feels keen please reply and I'll forward a copy. > Eventually I'm aiming to put the finished document on my website. I am interested. Thanks, Bev in TX -- https://mail.python.org/mailman/listinfo/python-list
Re: Friday Finking: Beyond implementing Unicode
On 13/06/20 4:47 AM, Terry Reedy wrote: On 6/12/2020 2:03 AM, DL Neil via Python-list wrote: Unicode has given us access to a wealth of mathematical and other symbols. Hardware and soft-/firm-ware flexibility enable us to move beyond and develop new 'standards'. Do we have opportunities to make computer programming more math-familiar and/or more logically-expressive, and thus easier to learn and practice? Could we develop Python to take advantage of these opportunities? ... Could we then also 'update' Python, to accept the wider range of symbols instead/in-addition to those currently in-use? Would such even constitute 'a good idea'? There was a recent thread on python-ideas discussing this. It started with arrow characters. There have been others. Am pleased to hear that it's neither 'new' nor 'way out there'... Am not subscribed to that list. Went looking for its archives, but failed - there's no "ideas" on (https://mail.python.org/mailman/listinfo). Please send a pointer... -- Regards =dn -- https://mail.python.org/mailman/listinfo/python-list
Re: Friday Finking: Beyond implementing Unicode
On 13/06/20 5:11 AM, Dennis Lee Bieber wrote: On Fri, 12 Jun 2020 18:03:55 +1200, DL Neil via Python-list declaimed the following: There is/was a language called "APL" (and yes the acronym means "A Programming Language", and yes it started the craze, through "B" (and BCPL), and yes, that brought us "C" - which you are more likely to have heard about - and yes then there were DataSci folk, presumably more numerate than literate, who thought the next letter to be "R". So, sad!?). R was preceded by S http://www.unige.ch/ses/sococ/cl/r/srdiff.e.html https://cran.r-project.org/doc/FAQ/R-FAQ.html#What-are-the-differences-between-R-and-S_003f (which, with some scrolling, produces... Oh dear, my sarcasm about being literately-challenged stands! APL was hopelessly keyboard-unfriendly, requiring multiple key-presses or 'over-typing' to produce those arithmetic-operator symbols - Not with a Tektronix APL terminal, and Xerox CP/V APL Specific design-for-purpose - hardware/software integration! remember, much of this was on mainframe 3270-style terminals, although later PC-implementations have existed (I can't comment on how 'active' any community might be). The over-typing was necessary to encode/produce the APL symbols which don't exist on a standard typewriter keyboard. Ugh! Many implementations also allowed for a spelled out version for special characters... $RHO for example, for the greek letter rho. To which my first reaction was "ugh!". However, I often prefer to have a named constant in my Python code - instead of "magic numbers", eg LINE_WIDTH = 79 # PEP-8 source-code characters per line I'm glad to have limited my APL-exposure to only reading about it during a 'Programming Languages' topic! (If you are 'into' functional programming you may like to explore further) I used it as a 3-credit independent study in my senior year (1980). All I was after was a passing grade to complete the credits for graduation. I'm slightly ashamed to admit that my fanciest program turned that Tektronix storage display tube terminal into a glorified Etch-a-Sketch (terminal had X/Y scroll wheels that the APL implementation could read). Hey, at least you gained access. I think my uni (when I was an u/grad) only had one graphic terminal which was kept in the computer room and thus only staff had access. Our introduction to graphics (using FORTRAN) had to be shown using 80x24 character-based terminals (DEC VT-52s, from memory). Drawing shapes was bad-enough, but demonstrations of rotation and translation became the very definition of ugly! I've been somewhat re-living those days, teaching myself how to play with Pygame (not a 'work' activity!), and learning how to move entities around on the screen (quite similar to HTML5, but sufficiently different to give pause). That said, the learning of such basic "building-blocks", four-plus decades ago, under-pins working in both/either/each, today! -- Regards =dn -- https://mail.python.org/mailman/listinfo/python-list
Re: Friday Finking: Beyond implementing Unicode
There was a recent thread on python-ideas discussing this. It started with arrow characters. There have been others. Am pleased to hear that it's neither 'new' nor 'way out there'... Am not subscribed to that list. Went looking for its archives, but failed - there's no "ideas" on (https://mail.python.org/mailman/listinfo). Please send a pointer... Apologies! Eventually remembered the second list of lists - the list of Python lists which are Python lists but not on the first list of Python lists... No wonder I'm dizzy! -- Regards =dn -- https://mail.python.org/mailman/listinfo/python-list
