🌐 Mailman 3 February 2023 - Python-list - python.org

TypeError: can only concatenate str (not "int") to str
by Hen Hanna Feb. 25, 2023

Feb. 25, 2023

TypeError: can only concatenate str (not "int") to str thanks for the comments, --- esp. 2 or 3 (?) ppl who directly addressed it or commented on it. py and pypy don't tell me what the (offending) int is (even tho' it'd be easy to show me the int, or number) because a Tuple, List... may produce a long output and they don't want to deal with ways of abbreviating it (with ....... ) and because User-defined Class object may cause another error while printing it. _________________________________________ TypeError: can only join an iterable Here too it'd help me if pypy (Jeannie) could tell me what the offending data object is.

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Re: Line continuation and comments
by Mark Bourne Feb. 25, 2023

Feb. 25, 2023

Personally, I don't particularly like the way you have to put multiline strings on the far left (rather than aligned with the rest of the scope) to avoid getting spaces at the beginning of each line. I find it makes it more difficult to see where the scope of the class/method/etc. actually ends, especially if there are multiple such strings. It's not too bad for strings defined at the module level (outer scope) though, and of course for docstrings the extra spaces at the beginning of each line don't matter. However, rather than using "+" to join strings as in your examples (which, as you suggest, is probably less efficient), I tend to use string literal concatenation which I gather is more efficient (treated as a single string at compile-time rather than joining separate strings at run-time). See <https://docs.python.org/3/reference/lexical_analysis.html#string-literal-co…>. For example: HelpText = ("Left click: Open spam\n" "Shift + Left click: Cook spam\n" "Right click: Crack egg\n" "Shift + Right click: Fry egg\n") The downside is having to put an explicit "\n" at the end of each line, but to me that's not as bad as having to align the content to the far left. Getting a bit more on topic, use of backslashes in strings is a bit different to backslashes for line continuation anyway. You could almost think of "\ (newline)" in a multiline string as being like an escape sequence meaning "don't actually put a newline character in the string here", in a similar way to "\n" meaning "put a newline character here" and "\t" meaning "put a tab character here". Mark. avi.e.gross(a)gmail.com wrote: > Good example, Rob, of how some people make what I consider RELIGIOUS edicts that one can easily violate if one wishes and it makes lots of sense in your example. > > Let me extend that. The goal was to store a character string consisting of multiple lines when printed that are all left-aligned. Had you written: > > HelpText = """ > Left click: Open spam > ... > Shift + Right click: Fry egg > """ > Then it would begin with an extra carriage return you did not want. Your example also ends with a carriage return because you closed the quotes on another line, so a \ on the last line of text (or moving the quotes to the end of the line) would be a way of avoiding that. > > Consider some alternatives I have seen that are in a sense ugly and may involve extra work for the interpreter unless it is byte compiled once. > > def someFunc(): > HelpText = > "Left click: Open spam" + "\n" + > "Shift + Left click: Cook spam" + "\n" + > ... > > Or the variant of: > HelpText = "Left click: Open spam\n" > HelpText += " Shift + Left click: Cook spam\n" > ... > > Or perhaps just dumping the multi-line text into a file beforehand and reading that into a string! > > def someFunc(): > > The backslash is not looking like such a bad idea! LOL! > > -----Original Message----- > From: Python-list <python-list-bounces+avi.e.gross=gmail.com(a)python.org> On Behalf Of Rob Cliffe via Python-list > Sent: Wednesday, February 22, 2023 2:08 PM > To: python-list(a)python.org > Subject: Re: Line continuation and comments > > > > On 22/02/2023 15:23, Paul Bryan wrote: >> Adding to this, there should be no reason now in recent versions of >> Python to ever use line continuation. Black goes so far as to state >> "backslashes are bad and should never be used": >> >> https://black.readthedocs.io/en/stable/the_black_code_style/future_sty >> le.html#using-backslashes-for-with-statements > > def someFunc(): > HelpText = """\ > Left click: Open spam > Shift + Left click: Cook spam > Right click: Crack egg > Shift + Right click: Fry egg > """ > > The initial backslash aligns the first line with the others (in a fixed font of course). > Best wishes > Rob Cliffe > -- > https://mail.python.org/mailman/listinfo/python-list >

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unpack, pack
by Hen Hanna Feb. 25, 2023

Feb. 25, 2023

when i unpack the string (or Seed) USENEARSEYNE , i get words like Sense, Sears, ........, Snare, Unary, .... (sarsen, seesee, senary, serene, unease, uneasy, usneae, usneas) (sensyne) How would i approach the PACKING function ? e.g. ... i want to find the string X that packs Apple, Pie, Apricot, Banana, Candy (packing doesn't require an English dictionary) and i want X to be short. Thanks! (is this in Vol.3 of Knuth?)

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Re: Find 6-letter words that are hidden (embedded) within
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

On Friday, February 24, 2023 at 1:18:28 PM UTC-8, David Raymond wrote: > > Find 6-letter words that are hidden (embedded) within each row of letters. > > The letters are in the correct order. > > > > 1. JSOYOMFUBELR > > 2. SCDUARWDRLYE > > 3. DASNAGEFERTY > > 4. CLULOOTSCEHN > > 5. USENEARSEYNE > > > The letters are in the correct order. -------- So this problem is not about Anagraming. > You can get every combination of 6 letters out of it with itertools.combinations like below. > Just implement the isWord function to return whether a string actually counts as a legit word or not. > 12 choose 6 is only 924 combinations to check, so shouldn't be too bad to check them all. > > > def isWord(word): > return True #Best left as an exercise to the reader > > startWord = "JSOYOMFUBELR" > subLetterCount = 6 > > foundWords = set() > > for letters in itertools.combinations(startWord, subLetterCount): > word = "".join(letters) > if word not in foundWords and isWord(word): > print(word) > foundWords.add(word) thank you... i could use the Pset below, too. # Factorial Python One-Liner def fac(n): return reduce(lambda x, y: x * y, range(1, n+1)) for i in range(1,11): print ( '\t', fac(i) ) # Power set Python One-Liner def Pset(L): return reduce(lambda z, x: z + [y + [x] for y in z], L, [[]]) print( '\n', Pset( [1,] )) print( '\n', Pset( [1,2,] )) print( '\n', Pset( [1,2,3] ))

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Not receiving posts
by Jim Byrnes Feb. 24, 2023

Feb. 24, 2023

I have been reading the python-list for some time now. At first via gemane and since it's demise via a subscription. Recently I noticed that I have not received any emails for quite sometime. I tried resubscribing but still have received no emails from the list. To my knowledge I have done nothing to warrant removal. Can you please check and see what I need to do to start receiving emails once more. regards, Jim Byrnes

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Find 6-letter words that are hidden (embedded) within
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

i just wrote a program, which... within [FunFunPython] finds: (funny, futon, python) ( 5- and 6- letter words ) (my program uses a Trie, but is pretty simple) Maybe someone would show me how it's done using itertools, Permutations, etc. Wouldn't it get too slow for Letter-Seeds longer than 11 letters or so? ______________________ Find 6-letter words that are hidden (embedded) within each row of letters. The letters are in the correct order. 1. JSOYOMFUBELR 2. SCDUARWDRLYE 3. DASNAGEFERTY 4. CLULOOTSCEHN 5. USENEARSEYNE

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Re: Why doesn't Python (error msg) tell me WHAT the actual (arg) values are ?
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

On Wednesday, February 22, 2023 at 11:57:45 PM UTC-8, Barry wrote: > > On 23 Feb 2023, at 01:39, Hen Hanna <henh...(a)gmail.com> wrote: > > > > On Wednesday, February 22, 2023 at 3:46:21 PM UTC-8, Hen Hanna wrote: > >> On Wednesday, February 22, 2023 at 12:05:34 PM UTC-8, Hen Hanna wrote: > >>>> py bug.py > >>> Traceback (most recent call last): > >>> File "C:\Usenet\bug.py", line 5, in <module> > >>> print( a + 12 ) > >>> TypeError: can only concatenate str (not "int") to str > >>> > >>> > >>> Why doesn't Python (error msg) do the obvious thing and tell me > >>> WHAT the actual (offending, arg) values are ? > >>> > >>> In many cases, it'd help to know what string the var A had , when the error occurred. > >>> ------------ i wouldn't have to put print(a) just above, to see. > >>> > >>> > >>> > >>> > >>> ( pypy doesn't do that either, but Python makes programming (debugging) so easy that i hardly feel any inconvenience.) > > > > > > i see that my example would be (even) clearER with this one-line change: > > > > py bug.py > > > > Traceback (most recent call last): > > > > File "C:\Usenet\bug.py", line 5, in <module> > > map( Func, fooBar( X, Y, X + Y )) > > > > TypeError: can only concatenate str (not "int") to str > > attempt to call + with 'abc', 123 <-------------- > > > >> i hope that NOW a few of you can see this as a genuine, (reasonable) question. > > > > Python seems so perfectly User-friendly that > > i 'm so curious (puzzled) that it doesn't do the very obvious and easy thing > > of giving me this info: > > > > attempt to call + with 'abc', 123 <-------------- > It is not easy to do that in a robust and reliable way for any object. > You can end up in the code to generate the error message itself breaking. > For example using unbounded CPU time when attempting to get the string repr of the variable. > > Barry > Python VM is seeing an "int" object (123) (and telling me that) ... so it should be easy to print that "int" object What does Python VM know ? and when does it know it ? it seems like it is being playful, teasing (or mean), and hiding the ball from me

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Re: semi colonic
by Greg Ewing Feb. 24, 2023

Feb. 24, 2023

On 24/02/23 9:26 am, avi.e.gross(a)gmail.com wrote: > Python One-Liners: Write Concise, Eloquent Python Like a Professional Illustrated Edition > by Christian Mayer (Author) I didn't know there were any Professional Illustrated Editions writing Pythom. You learn something every day! :-) -- Greg

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Re: putting JUNK at the end of a [.py] file
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

On Thursday, February 23, 2023 at 9:17:05 PM UTC-8, Thomas Passin wrote: > On 2/23/2023 7:21 PM, Hen Hanna wrote: > > > > in a LaTeX file, after the (1st) \end{document} line, > > i can put any random Junk i want (afterwards) until the end of the file. > > > > > > Is there a similar Method for a .py file ? > > > > Since i know of no such trick, i sometimes put this (below) at the end of a .py file. > > > > > > > > dummy= (""" junk and more junk > > words in Dict > > 239 words in Dict > > ((( notes or Code fragmetns ))) > > """) > > > > > > > > ** maybe i don't need the dummy= but it looks better. > You can just put it in triple quotes, no need to assign the string to a > variable. Or make each line a comment. thanks for the rare concise comment taht also seems devoid of insulting attitude. ( i still can't tell one person from another, but i did notice that one person sent me email that was really long, insulting, and creepy ) i guess i use (""" """) because i wish it (this feature) came in matching pairs. and put dummy= to remind myself and to tell the compiler, obivously this Var is unused to feel free to ignore it.

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Re: semi colonic
by Hen Hanna Feb. 24, 2023

Feb. 24, 2023

On Wednesday, February 22, 2023 at 6:21:13 PM UTC-8, Rob Cliffe wrote: > On 23/02/2023 02:04, Thomas Passin wrote: > > On 2/22/2023 7:58 PM, avi.e...(a)gmail.com wrote: > >> > >> > >> So can anyone point to places in Python where a semicolon is part of > >> a best > >> or even good way to do anything? > > > > I use the semicolon (once in a while) is for quick debugging. I > > might add as line like, perhaps, > > > > import os; print(os.path.exists(filename)) > > > > This way I can get rid of the debugging statement by deleting that > > single line. This is non only quicker but I'm less likely to delete > > too much by mistake. > > > I do exactly the same. > Rob Cliffe i sometimes put extra commas... as: [ 1, 2, 3, 4, ] so it is (or may be) easier to add things later. ----------- i can think of putting extra final ; for the same reason.

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