Re: Symlinks already present
On 2/09/20 6:55 am, Eryk Sun wrote:
According to POSIX (st_dev, st_ino), it's the same directory, yet the
".." entry evaluates depending on the path parsing context:
>>> os.lstat('test1/spam/..').st_ino == os.lstat('test1').st_ino
True
>>> os.lstat('test2/spam/..').st_ino == os.lstat('test2').st_ino
True
What happens if you go one level deeper? I.e. is
os.lstat('test1/spam/eggs/../..').st_ino == os.lstat('test1').st_ino
and
os.lstat('test2/spam/eggs/../..').st_ino == os.lstat('test2').st_ino
?
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Re: Symlinks already present
On 9/3/20, Greg Ewing wrote:
> On 2/09/20 6:55 am, Eryk Sun wrote:
>> According to POSIX (st_dev, st_ino), it's the same directory, yet the
>> ".." entry evaluates depending on the path parsing context:
>>
>> >>> os.lstat('test1/spam/..').st_ino == os.lstat('test1').st_ino
>> True
>> >>> os.lstat('test2/spam/..').st_ino == os.lstat('test2').st_ino
>> True
>
> What happens if you go one level deeper? I.e. is
> os.lstat('test1/spam/eggs/../..').st_ino == os.lstat('test1').st_ino
> and
> os.lstat('test2/spam/eggs/../..').st_ino == os.lstat('test2').st_ino
> ?
Those two examples return true. Going a level deeper to 'spam/eggs'
doesn't change the behavior of the graft at "test2/spam".
An interesting case is bind mounting a directory on one of its child
directories. For example, if "spam" is mounted on "spam/mount_spam":
>>> s = os.lstat('spam/mount_spam/mount_spam/..')
>>> s.st_ino == os.lstat('spam').st_ino
True
The namespace graft only occurs at "spam/mount_spam". So
"spam/mount_spam/mount_spam" is the original filesystem directory, for
which the ".." entry references "spam". It's also consistent with
"spam/mount_spam" being bound to "spam".
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Regex to change multiple lines
Hi. I've on file, containing multiple lines, and I need to change every
occurrence of a sequence between two chars, in this case "%%".
-- original
This is the %%text that i must modify%%, on a line, %%but also
on the others%% that are following
I need to change to
-- desidered
This is the text that i must modify, on a line, but also
on the others that are following
I've tryed with this small code
rebarredtext = r'~~([^>]*)~~'
text = mycontent
for line in re.findall(rebarredtext, text):
text = text.replace("~~" + line + "~~", "" + line + "")
but it changes only the biggest occurrence: how can I do to change all
occurrences? I'm really a regex newbie, TIA
-- test
This is the text that i must modify%%, on a line, %%but also
on the others that are following
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Re: Regex to change multiple lines
On Fri, Sep 4, 2020 at 12:16 AM Termoregolato wrote: > > Hi. I've on file, containing multiple lines, and I need to change every > occurrence of a sequence between two chars, in this case "%%". > > -- original > This is the %%text that i must modify%%, on a line, %%but also > on the others%% that are following > > I need to change to > > -- desidered > This is the text that i must modify, on a line, but also > on the others that are following > > I've tryed with this small code > > rebarredtext = r'~~([^>]*)~~' The trouble here is that the bit in the middle will take as much as it possibly can, even though that includes the marker. (BTW, you're inconsistent here as to whether the marker is "%%" or "~~".) I'm not sure why you're excluding ">" from this group, but I presume that that's intentional. To solve this, you can make the asterisk "non-greedy" by adding a question mark after it: rebarredtext = r'~~([^>]*?)~~' Now it matches as *little* as it possibly can. Additionally, you can get the regex engine to do the work of replacing, too. re.sub(rebarredtext, r'\1', txt) That'll do the whole loop and everything; it replaces every match of the regex with the given replacement text, where "\1" takes whatever was inside the parentheses. Regular expressions are incredibly powerful, but unfortunately hard to debug, so all you can do is test and tinker :) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Regex to change multiple lines
On 2020-09-03 16:10, Termoregolato wrote:
> -- original
> This is the %%text that i must modify%%, on a line, %%but also
> on the others%% that are following
>
> I need to change to
>
> -- desidered
> This is the text that i must modify, on a line, but
> also on the others that are following
Should be able to use
:%s/%%\(\_.\{-}\)%%/\1<\/del>/g
It simplifies slightly if you use a different delimiter
:%s@%%\(\_.\{-}\)%%@\1@g
-tim
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Re: Regex to change multiple lines
Derp, sorry about the noise. I mistook this message for a similar
dialog over on the Vim mailing list.
For Python, you want
re.sub(r"%%(.*?)%%", r"\1", s, flags=re.S)
or put the flag inline
re.sub(r"(?s)%%(.*?)%%", r"\1", s)
-tim
On 2020-09-03 09:27, Tim Chase wrote:
> On 2020-09-03 16:10, Termoregolato wrote:
> > -- original
> > This is the %%text that i must modify%%, on a line, %%but also
> > on the others%% that are following
> >
> > I need to change to
> >
> > -- desidered
> > This is the text that i must modify, on a line,
> > but also on the others that are following
>
> Should be able to use
>
> :%s/%%\(\_.\{-}\)%%/\1<\/del>/g
>
> It simplifies slightly if you use a different delimiter
>
> :%s@%%\(\_.\{-}\)%%@\1@g
>
> -tim
>
>
>
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Re: What kind of magic do I need to get python to talk to Excel xlsm file?
If you don't need to do any specific data analysis using pandas, try openpyxl. It will read xlsm files and it quite straight forward to use. https://openpyxl.readthedocs.io/en/stable/ pip install openpyxl. Ian -- https://mail.python.org/mailman/listinfo/python-list
Replacement for pygtk?
Many years ago I wrote an app that uses pygtk for it's GUI. I still use the app occasionally, and would like to keep it alive. Emerge informs me that dev-python/pygtk is scheduled for removal. Is pygobject the replacement for pygtk? -- Grant -- https://mail.python.org/mailman/listinfo/python-list
Pyserial and some half-duplex woes.
Hey All, I am using Microchip's Python program to download code to a PIC32 microprocessor via Pyserial. There is also Microchip's bootloader code running on the PIC side. This works very well using the a standard serial hardware directly connected to a USB to serial adapter to one of the PIC's UARTs. However in our application the hardware is a single wire thus requiring a half-duplex communications. Fortunately Microchip's protocol lends itself to half-duplex communications, however the problem is that both the PIC and the Python program will receive an echo when one of the other transmits due to the hardware design. It other words the PIC will receive what it transmits and the same on the Python side. The PIC side is easily fixed by simply turning off receive during transmit. I don't think I can do this on the Python side at least there nothing in Pyserial's documentation that you can do that. I have tried to do some flushing of the receive buffer, but I haven't been too successful. Perhaps that is due to timing. I thought I would reach out to see if anyone may have had a similar experience. Thanks for any help. Mark -- https://mail.python.org/mailman/listinfo/python-list
Re: Regex to change multiple lines
Il 03/09/20 16:10, Termoregolato wrote: I need to change every occurrence of a sequence between two chars Thanks to all for your replies, it's time to learn regular expressions, but now I've some valid pointers from you. The work I must do here, to explain, is to get some markdown files, and add the strikethrough in a different color from the original, so I've do a bit of confusion between markdown "~~" and my "%%" in examples, where I wanted to reduce the number of lines. -- https://mail.python.org/mailman/listinfo/python-list
Re: Replacement for pygtk?
On 2020-09-03, Grant Edwards wrote: > [...] > > Is pygobject the replacement for pygtk? It seems to be. I've started porting my pygtk app, and it's going pretty smoothly. I've already got my two custom widgets working. Oddly, the main module provided by the gobject package is called "gi". -- https://mail.python.org/mailman/listinfo/python-list
Re: Regex to change multiple lines
On Fri, Sep 4, 2020 at 5:36 AM Termoregolato wrote: > > Il 03/09/20 16:10, Termoregolato wrote: > > > I need to change every occurrence of a sequence between two chars > > Thanks to all for your replies, it's time to learn regular expressions, > but now I've some valid pointers from you. > > The work I must do here, to explain, is to get some markdown files, and > add the strikethrough in a different color from the original, so I've do > a bit of confusion between markdown "~~" and my "%%" in examples, where > I wanted to reduce the number of lines. Hmm. Have you considered using CSS to do this? Markdown is generally fairly easy to style with CSS. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Replacement for pygtk?
On 9/3/20 1:17 PM, Grant Edwards wrote: > On 2020-09-03, Grant Edwards wrote: >> [...] >> >> Is pygobject the replacement for pygtk? > > It seems to be. I've started porting my pygtk app, and it's going > pretty smoothly. I've already got my two custom widgets working. > Oddly, the main module provided by the gobject package is called "gi". It stands for "gobject introspection." The nice thing about the gi module is it can wrap any gobject-based library, not just GTK+ proper. So if someone made a custom widget in Vala, for example, you could access it via gi. It's a neat idea. My only problem with it is the resulting Python API is not always as pythonic as pygtk code was. I can't think of any specific examples at the moment, however. It's pretty much good enough to not care too much. Similar arguments can be made against PyQt as well. Especially with PyQt the end result feels a bit like writing C++ with a python syntax. -- https://mail.python.org/mailman/listinfo/python-list
Re: Threading plus multiprocessing plus cv2 error
On Sat, Aug 29, 2020 at 06:24:10PM +1000, John O'Hagan wrote:
> Dear list
>
> Thanks to this list, I haven't needed to ask a question for
> a very long time, but this one has me stumped.
>
> Here's the minimal 3.8 code, on Debian testing:
>
> -
> from multiprocessing import Process
> from threading import Thread
> from time import sleep
> import cv2
>
> def show(im, title, location):
> cv2.startWindowThread()
> cv2.namedWindow(title)
> cv2.moveWindow(title, *location)
> cv2.imshow(title, im)
> sleep(2) #just to keep window open
>
> im1 = cv2.imread('/path/to/image1')
> im2 = cv2.imread('/path/to/image2')
>
> Thread(target=show, args=(im1, 'im1', (600,0))).start()
> sleep(1)
> Process(target=show, args=(im2, 'im2', (0, 0))).start()
> -
>
> Here's the error:
>
> -
> [xcb] Unknown sequence number while processing queue
> [xcb] Most likely this is a multi-threaded client and XInitThreads has
> not been called
> [xcb] Aborting, sorry about that.
> python3: ../../src/xcb_io.c:260: poll_for_event: Assertion
> `!xcb_xlib_threads_sequence_lost' failed.
> -
It's hard to say EXACTLY what the nature of the error is, without
knowing what the underlying libraries are doing. But from this one
thing is clear: You are starting a new thread, and then forking a new
process. This is very likely to break, because contrary to what
several people have said in this thread, the new thread WILL NOT be
copied to the new program, so in the new process, part of your program
is literally missing. This can have all kinds of consequences.
For that reason, you can't spawn a new thread and then fork a new
process, in that order, and expect your program to function correctly.
Whatever your program does that depends on that new thread won't work
correctly, because that thread does not exist in the child (new
process). You can, however, do those things in the reverse order and
it should be fine... new threads will be started in both processes
(unless you take steps to ensure only one of the processes creates the
thread). Both processes retain their integrity and should run fine.
> There's no error without the sleep(1), nor if the Process is started
> before the Thread, nor if two Processes are used instead, nor if two
> Threads are used instead. IOW the error only occurs if a Thread is
> started first, and a Process is started a little later.
Hopefully my explanation above makes it clear why all of those things
are true, other than the sleep() issue. That one is most likely just
a timing issue: Whatever resource is causing the problem hasn't been
set up yet or the critical thread or process has already finished
execution before the issue can arise, or something of the sort. When
you start new threads or processes, usually there's some delay as your
OS schedules each process/thread to run, which is somewhat random
based on how the scheduler works and how loaded the system is. Such
timing problems (bugs that seem to happen randomly with each run of
the program, or over time in a long-executing program) are common in
multi-threaded programs that are written incorrectly, especially when
the state of one thread depends on the state of the other thread, and
the two don't synchronize correctly. This is another way that the
first problem above can manifest, too: The threads can't synchronize
because one of them does not exist!
Hope that helps.
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compile error building building Python-3.8.5 on Debian 8.11 (yes, old!)
I've built 3.8.5 on a few other machines happily recently. Building Python 3.8.5, running make and gcc (Debian 4.9.2-10+deb8u2) 4.9.2 I get this: % gcc -pthread -c -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall-std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -I./Include/internal -I. -I./Include-DPy_BUILD_CORE -o Modules/gcmodule.o Modules/gcmodule.c Modules/gcmodule.c: In function 'collect.constprop': Modules/gcmodule.c:126:50: warning: array subscript is above array bounds [-Warray-bounds] #define GEN_HEAD(state, n) (&(state)->generations[n].head) ^ Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD' gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation)); ^ Modules/gcmodule.c:126:50: warning: array subscript is above array bounds [-Warray-bounds] #define GEN_HEAD(state, n) (&(state)->generations[n].head) ^ Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD' gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation)); ^ Modules/gcmodule.c:126:50: warning: array subscript is above array bounds [-Warray-bounds] #define GEN_HEAD(state, n) (&(state)->generations[n].head) ^ Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD' gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation)); ^ Any thoughts? I'll try a few other minor versions meanwhile... Cheers, Cameron Simpson -- https://mail.python.org/mailman/listinfo/python-list
Re: compile error building building Python-3.8.5 on Debian 8.11 (yes, old!)
On Fri, Sep 4, 2020 at 3:01 PM Cameron Simpson wrote: > > I've built 3.8.5 on a few other machines happily recently. > > Building Python 3.8.5, running make and gcc (Debian 4.9.2-10+deb8u2) > 4.9.2 I get this: > > % gcc -pthread -c -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv > -O3 -Wall-std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter > -Wno-missing-field-initializers -Werror=implicit-function-declaration > -I./Include/internal -I. -I./Include-DPy_BUILD_CORE -o > Modules/gcmodule.o Modules/gcmodule.c > Modules/gcmodule.c: In function 'collect.constprop': > Modules/gcmodule.c:126:50: warning: array subscript is above array bounds > [-Warray-bounds] > #define GEN_HEAD(state, n) (&(state)->generations[n].head) > ^ > Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD' > gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation)); >^ > Modules/gcmodule.c:126:50: warning: array subscript is above array bounds > [-Warray-bounds] > #define GEN_HEAD(state, n) (&(state)->generations[n].head) > ^ > Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD' > gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation)); >^ > Modules/gcmodule.c:126:50: warning: array subscript is above array bounds > [-Warray-bounds] > #define GEN_HEAD(state, n) (&(state)->generations[n].head) > ^ > Modules/gcmodule.c:1036:43: note: in expansion of macro 'GEN_HEAD' > gc_list_merge(GEN_HEAD(state, i), GEN_HEAD(state, generation)); >^ > > Any thoughts? > Those are warnings; if there are errors that block compilation, they aren't in what you quoted above. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
