Re: Why no '|' operator for dict?
2018-02-05 9:14 GMT+01:00 Ian Kelly : > On Mon, Feb 5, 2018 at 12:35 AM, Frank Millman wrote: >> 2. Is there a better way to do what I want? > > The dict.items() view is explicitly set-like and can be unioned, so > you can do this: > > py> dict(d1.items() | d2.items()) > > As to the question of which value will appear in the union in the case > of duplicate keys, it will be whichever one arbitrarily appears later > in the iteration order of the intermediate set. Since Python 3.5, it is also possible to use PEP448 generalized unpacking: dict([*d1.items(), *d2.items()]) In which case the value that appears in case of duplicate keys is better defined, it will be the one appearing in the last dictionnary. -- https://mail.python.org/mailman/listinfo/python-list
Re: comapring 2 sequences of DNA ouput the silent and non mutations
2016-10-29 21:38 GMT+02:00 : > > Code: > > [...] > > for i in range (len(protein) & len(seq1)) : > > if protein[i] != mutantPRO[i] : >print (protein[i] + str(i) + mutantPRO[i]) >A+= 1 > else: > if seq1[i:i+3] != mutant[i:i+3]: > print(protein[i] + str(i) + mutantPRO[i] +' Silent mutation ') > print(seq1[i:i+3] + mutant[i:i+3]) > B+= 1 Hi, The problem here is that you try to mix two different index in one variable. Instead, you need to do something like this: #i index protein #j index DNA for i in range (len(protein)) : j = i*3 if protein[i] != mutantPRO[i] : print (protein[i] + str(i) + mutantPRO[i]) A+= 1 else: if seq1[j:j+3] != mutant[j:j+3]: print(protein[i] + str(i) + mutantPRO[i] +' Silent mutation ') print(seq1[j:j+3] + mutant[j:j+3]) B+=1 -- https://mail.python.org/mailman/listinfo/python-list
Re: UserList - which methods needs to be overriden?
2016-06-10 10:37 GMT+02:00 Peter Otten <__pete...@web.de>: > > Nagy László Zsolt wrote: > > > I'm not sure wich one is the best. Peter wrote that UserList was left in > > collections only for backward compatiblity. This might be a point > > I'll take that back. I looked around and found no evidence for my claim. > Only MutableString was removed during the transition to Python 3. > > Sorry for the confusion. > > Up to Python 2.6, the docs of UserList had a note stating that: This module is available for backward compatibility only. If you are writing code that does not need to work with versions of Python earlier than Python 2.2, please consider subclassing directly from the built-in list type. This was changed in Python 2.7 to: When Python 2.2 was released, many of the use cases for this class were subsumed by the ability to subclass list directly. However, a handful of use cases remain. So I think the intention was that the ability to subclass list would remove the need to subclass UserList, but it was later realised that it is not totally the case. -- https://mail.python.org/mailman/listinfo/python-list
Re: psutil.boot_time() ... doesn't ?
Hello, You may want to read PEP 418 which nicely summaries the different clock available on each platform and their limitations. It looks like CLOCK_BOOTTIME is what you want but it is only available on Linux. Regards, Maxime. Le mer. 6 nov. 2019 à 18:23, R.Wieser a écrit : > Hello all, > > I was doing a "lets print some time-related data", and also diaplayed the > result of "psutil.boot_time()". > > Somewhere while doing that I saw that my clock was off, so I used the > "date" > command to rectify it. > > The thing is, after that the result of "psutil.boot_time()" was changed - > and that I did (and do) not expect. :-( > (Remark: the difference was exactly the same as the change I made with the > "date" command). > > Question: Is there a way to retrieve the "last boot" time /without/ it > getting changed by ... whatever ? > > Regards, > Rudy Wieser > > > > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
Re: Fun with IO
Hi, Le ven. 17 janv. 2020 à 20:11, Frank Millman a écrit : > It works perfectly. However, some pdf's can be large, and there could be > concurrent requests, so I wanted to minimise the memory footprint. So I > tried passing the client_writer directly to the handler - > > await pdf_handler(client_writer) > client_writer.write(b'\r\n') > > It works! ReportLab accepts client_writer as a file-like object, and > writes to it directly. I cannot use chunking, so I just let it do its > thing. > > Can anyone see any problem with this? > > If the socket is slower than the PDF generation (which is probably always the case, unless you have a very fast network), it will still have to be buffered in memory (in this case in the writer buffer). Since writer.write is non-blocking but is not a coroutine, it has to buffer. There is an interesting blog post about that here that I recommend reading: https://lucumr.pocoo.org/2020/1/1/async-pressure/ Unfortunately, there is no way to avoid buffering the entire pdf in memory without modifying reportlab to make it async-aware. This version is still better than the one with BytesIO though because in that version the pdf was buffered twice, once in BytesIO and once in the writer, although you can fix that by using await writer.drain() after each write and then the two versions are essentially equivalent. Regards, Maxime. -- https://mail.python.org/mailman/listinfo/python-list
Re: Is there a log file that tracks every statement that is being executed when a program is running?
Hi,
You can use the trace module for that:
https://docs.python.org/3.8/library/trace.html
Personally I tend to put print statement at strategic places instead, I
find that easier to analyse than a full trace but YMMV.
Maxime
Le dim. 25 oct. 2020 à 01:25, Steve a écrit :
> This would seriously help troubleshooting for me. I updated a data file
> and
> now my main program is choking on it. When the program encounters an
> error,
> it dumps a bit of information to the screen for a few steps before the
> error
> but that is not enough.
>
>
>
>
> Footnote:
> English sprakers on a roller coaster: "W"
> Spanish speakers on a rollercoaster: " Nosostros"
>
> -Original Message-
> From: Python-list On
> Behalf Of shrimp_banana
> Sent: Saturday, October 17, 2020 9:47 PM
> To: python-list@python.org
> Subject: Re: File Name issue
>
> On 10/17/20 4:12 PM, Steve wrote:
> > The line:
> > with open("HOURLYLOG.txt", 'r') as infile:
> > works but, when I rename the file, the line:
> > with open("HOURLY-LOG.txt", 'r') as infile:
> > does not. The complaint is: Cannot Assign to operator > > However, I
> have:
> > BPM_O2s=open("BPM-O2-Readings.txt","a")
> > And it works.
> >
> > At first, I thought the issue was due to having the - in the filename.
> >
> > Is there a fix or explanation for this?
> > Steve
>
> I am unsure if this will help but you could try putting an r in front of
> the
> quotes to make it take raw data only.
> ie.
>
> with open(r"HOURLY-LOG.txt", 'r') as infile
> --
> https://mail.python.org/mailman/listinfo/python-list
>
> --
> https://mail.python.org/mailman/listinfo/python-list
>
--
https://mail.python.org/mailman/listinfo/python-list
Re: Question about asyncio and blocking operations
2016-01-28 17:53 GMT+01:00 Ian Kelly : > On Thu, Jan 28, 2016 at 9:40 AM, Frank Millman wrote: > > > The caller requests some data from the database like this. > > > >return_queue = asyncio.Queue() > >sql = 'SELECT ...' > >request_queue.put((return_queue, sql)) > > Note that since this is a queue.Queue, the put call has the potential > to block your entire event loop. > > Actually, I don't think you actually need an asyncio.Queue. You could use a simple deque as a buffer, and call fetchmany() when it is empty, like that (untested): class AsyncCursor: """Wraps a DB cursor and provide async method for blocking operations""" def __init__(self, cur, loop=None): if loop is None: loop = asyncio.get_event_loop() self._loop = loop self._cur = cur self._queue = deque() def __getattr__(self, attr): return getattr(self._cur, attr) def __setattr__(self, attr, value): return setattr(self._cur, attr, value) async def execute(self, operation, params): return await self._loop.run_in_executor(self._cur.execute, operation, params) async def fetchall(self): return await self._loop.run_in_executor(self._cur.fetchall) async def fetchone(self): return await self._loop.run_in_executor(self._cur.fetchone) async def fetchmany(self, size=None): return await self._loop.run_in_executor(self._cur.fetchmany, size) async def __aiter__(self): return self async def __anext__(self): if self._queue.empty(): rows = await self.fetchmany() if not rows: raise StopAsyncIteration() self._queue.extend(rows) return self._queue.popleft() -- https://mail.python.org/mailman/listinfo/python-list
Re: Cannot step through asynchronous iterator manually
2016-01-30 11:51 GMT+01:00 Frank Millman :
> "Chris Angelico" wrote in message
> news:CAPTjJmoAmVNTCKq7QYaDRNQ67Gcg9TxSXYXCrY==s9djjna...@mail.gmail.com...
>
>
>> On Sat, Jan 30, 2016 at 7:22 PM, Frank Millman
>> wrote:
>> > We had a recent discussion about the best way to do this, and ChrisA
>> > suggested the following, which I liked -
>> >
>> >cur.execute('SELECT ...)
>> >try:
>> >row = next(cur)
>> >except StopIteration:
>> ># row does not exist
>> >else:
>> >try:
>> >next_row = next(cur)
>> >except StopIteration:
>> ># row does exist
>> >else:
>> ># raise exception
>> >
>> > Now that I have gone async, I want to do the same with an asynchronous
>> > iterator.
>>
>
>
I might be a bit off-topic, but why don't you simply use cursor.rowcount?
For a pure iterator-based solution, I would do something like this (admitly
a bit cryptic, but iterator-based solutions often are :-) :
async def get_uniqu(ait):
async for row in ait:
break
else:
raise NotEnoughtRows()
async for _ in ait:
raise TooManyRows()
return row
--
https://mail.python.org/mailman/listinfo/python-list
Re: Broken IF statement
2015-01-12 22:19 GMT+01:00 : > > https://bpaste.net/show/93be9e15634b <--- Line 19 through 22 > > At all times, my program is assigning the object priority of 0, even if one already exists in the database with a priority of 0 (it's supposed to be assigning it a priority of 1 in those cases). > > I'm a non developer trying to fix a freelancer's code. Would anybody be able to suggest changes to the IF logic that might be able to fix it, assuming the statements in the code provided look flawed? > > Thanks... > -- > https://mail.python.org/mailman/listinfo/python-list This line: obj, created = SocialAccount.objects.get_or_create(...) suggest you are using Django. If it is the case you have to add obj.save() after changing the priority to send the new value to the DB. Best, Maxime -- https://mail.python.org/mailman/listinfo/python-list
Re: Function decorator having arguments is complicated
Le lun. 27 avr. 2015 à 04:39, Makoto Kuwata a écrit : > > If function decorator notation could take arguments, > decorator definition would be more simple: > > def multiply(func, n): > def newfunc(*args, **kwargs): > return n * func(*args, **kwargs) > return newfunc > > @multiply 4 # ex: @decorator arg1, arg2, arg3 > def f1(x, y): > return x+y > > > How do you think about this idea? > David Beazley has a nice trick [1] to allow optional argument in decorators: def logged(func=None, level=logging.DEBUG, message=None): if func is None: return partial(logged, level=level, message=message) @wraps(func) def wrapper(*args, **kwargs): log.log(level, message) return func(*args, **kwargs) return wrapper I think that solve your problem nicely, and that it is quite readable. [1] Amongst a heap of other cool tricks, in his Python Cookbook Regards, Maxime -- https://mail.python.org/mailman/listinfo/python-list
