Re: [Tutor] Looking for some direction
On 12/05/19 10:57 AM, Alan Gauld via Tutor wrote: On 11/05/2019 19:59, Cranky Frankie wrote: ... 1) For the IDE I'm most comfortable with Netbeans/Java, In that case use Netbeans. I use Netbeans myself when working with Java and have played with its Python implementation and its OK. Personally for serious Python work I just use vim and 3 consoles, but that's a matter of taste. but you should minimise the number of learning points and learning a new IDE while also learning OOP (and a GUI framework?) is just adding extra work. "3 consoles": what is the purpose of each? (my first reaction stemmed from many editors including a built-in console) -- Regards =dn ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Collating date data from a csv file
Hi Dave, I also volunteer to do PAT safety testing during my "20% time". Clambering around Snowdonia as a boy, I eschewed* the Rheilffordd yr Wyddfa/SMR in favor of shanks' pony... * OK, I was made to...! For the good of my soul??? On 9/05/19 8:04 AM, Dave Hill wrote: I have a csv file which details the results of equipment tests, I carry out PAT testing as a volunteer at a heriatge railway in N. Wales. I want to extract how many items were tested on each test day. So far I have generated a List of test dates, but I am now stalled at how to efficiently count numbers tested on each date. Can I have a list of tuples, where one item is the date and the second the count? or is there a better construct? Thanks in advance, Dave For completeness, I have listed below an extract from a target file, where the 10 digit number is the UNIX timestamp 182 1515001232 Toaster 13 2000 1 183 1515001259 Contact Grill 13 2000 1 245 1515001367 3G Cube Adaptor 13 0 1 246 1515001396 13A IEC Lead 5 0 1 248 1515001415 Worktop Light 3 30 1 420 1515001440 Fly killer 0 0 1 424 1515001461 Dairy fridge 13 0 1 427 1513277293 Fire 13 0 1 429 1515001489 Toaster Avanti 13 0 1 When you say "target file", is this coming off the tester via a link cable to your PC, or are you capturing by hand to a spreadsheet? A tactic which many people 'miss' is that a workbook may contain multiple spreadsheets, and that the data on one spreadsheet may be auto-magically 'copied' onto another. Thus if the above is data coming off the PAT into one spreadsheet, I would immediately create a more meaningful sheet, 'for human consumption', which has column headings and converts (re-formats) the timestamp into a readable date (as suggested elsewhere), but is otherwise pretty-much a direct copy. We now have a sheet used for data capture/computer processing and something separate (and prettier) as a report/presentation for people. From the spec, above, we are only interested in the date. Remember that considering the whole timestamp only makes life confusing. So convert them (only) to dates. These can be strings because Python compares strings as easily as dates! The time component could be retained if sequence (of testing) might be important. The sad reality is that a daily count could be accomplished in either LO-Writer or MS-Excel. No reason why you shouldn't use Python though. (Assuming that the data appears in (forward or reverse) date sequence) Read-in the data sheet/CSV file, row-by-row, taking note of the date of the first data-entry, and starting to count from one. Then increment for each row where the date matches. When the dates don't match, report, reset the counter, and note the new date. How will you lay-out and present this report? Another spreadsheet? Screen? Paper? When you say "count numbers tested on each date", the above method will let you know a (single) daily total of tests-performed. Did you (also) mean that you want to track how many of tests were performed within categories of devices, eg how many toasters on the one day? In which case, further design consideration is required, eg which devices fit into which category and how to match "Toaster" with "Toaster Avanti"... -- Regards =dn ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looking for some direction
On 12/05/2019 00:24, David L Neil wrote: > "3 consoles": what is the purpose of each? > (my first reaction stemmed from many editors including a built-in console) One for vim, One for the Python interpreter One for an OS shell used for running/testing the app plus any miscellaneous Unixy type things I need to do (sed/grep/awk/git etc). I'll usually also have a web browser for reading documentation if necessary, although that's mostly done in the interpreter using dir()/help(). Alt-Tab and the X cut 'n paste mechanism provides enough integration between windows. -- 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 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Local variable look up outside the function and method
In the following the function, x is reachable outside the scope of foo function. In [1]: x = 10 In [2]: def foo(): ...: return x ...: In [3]: print(foo()) 10 But why it is not the case when the look up happens inside a instance method of a class? In [1]: class Foo: ...: x = 10 ...: def bar(self): ...: return x ...: In [2]: Foo().bar() --- NameError Traceback (most recent call last) in > 1 Foo().bar() in bar(self) 2 x = 10 3 def bar(self): > 4 return x NameError: name 'x' is not defined I figured I have to access it like: In [1]: class Foo: ...: x = 10 ...: def bar(self): ...: return self.__class__.x ...: ...: print(Foo().bar()) 10 Just want to know how these search happens in 2 contexts. Thanks, Arup Rakshit a...@zeit.io ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Local variable look up outside the function and method
On 12/05/2019 14:04, Arup Rakshit wrote: The first case x is a global variable - which in Python really means module level. In the second case you have placed it inside Foo so you need to specify that that is where it is located. Classes encapsulate their own methods and attributes, that is one of their purposes. and just as you can't access a method without preceding it with self similarly you can't access an attribute without providing the object or class reference. > I figured I have to access it like: > > In [1]: class Foo: >...: x = 10 >...: def bar(self): >...: return self.__class__.x Remember that any time you find yourself using dunder techniques ask if there is an easier way. There usually is... You can just use return self.x or, possibly better: return Foo.x You know x is declared in the context of Foo so refer to it directly. The self approach runs the risk of an instance attribute of the same name being created and overriding the class attribute. (But sometimes that's what you want.) If you had an inheritance hierarchy where x was defined in multiple places the .__class__ approach would work better (probably even be needed). But in most cases these kinds of variables are defined once in the class and you are safe to access it by name - and it makes the code more readable and unambiguous. -- 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 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Local variable look up outside the function and method
Hello Arup,
> In the following the function, x is reachable outside the scope of foo
> function.
> In [1]: x = 10
> In [2]: def foo():
>...: return x
> In [3]: print(foo())
> 10
> But why it is not the case when the look up happens inside a
> instance method of a class?
>
> In [1]: class Foo:
>...: x = 10
>...: def bar(self):
>...: return x
> In [2]: Foo().bar()
> ---
> NameError Traceback (most recent call last)
> in
> > 1 Foo().bar()
>
> in bar(self)
> 2 x = 10
> 3 def bar(self):
> > 4 return x
>
> NameError: name 'x' is not defined
>
> I figured I have to access it like:
>
> In [1]: class Foo:
>...: x = 10
>...: def bar(self):
>...: return self.__class__.x
>...:
>...: print(Foo().bar())
> 10
>
> Just want to know how these search happens in 2 contexts.
Probably the following is the best section of the documentation to
read:
https://docs.python.org/3/tutorial/classes.html#class-and-instance-variables
Here's also a little sample that may help. By the way, I wouldn't
normally be doing things like "unset self.x" and creating those
peculiar methods, but I thought it might be instructive in this
case. This is using the same sort of technique you were with your
class called Foo. (I don't know all of the reasons why to inherit
from object, but I usually do...)
class Foo(object):
x = 10 # -- class variable
def __init__(self):
self.y = 20 # -- instance variable named 'y'
def setinstancex(self, x):
self.x = x
def removeinstancex(self):
del self.x
def report(self):
return (self.x, self.y)
if __name__ == '__main__':
f = Foo()
print('# -- f.x retrieves class value, f.y instance value')
print('f.x = %s, f.y = %s, Foo.x = %s' % (f.x, f.y, Foo.x))
print()
f.setinstancex(3.14159)
print('# -- f.x retrieves instance value, f.y instance value')
print('f.x = %s, f.y = %s, Foo.x = %s' % (f.x, f.y, Foo.x))
print()
print('# -- warning, we are about to change the value for Foo.x')
print()
Foo.x = 6.022141e-23
print('# -- f.x retrieves class value, f.y instance value')
print('f.x = %s, f.y = %s, Foo.x = %s' % (f.x, f.y, Foo.x))
print()
f.removeinstancex()
print('# -- f.x retrieves class value, f.y instance value')
print('f.x = %s, f.y = %s, Foo.x = %s' % (f.x, f.y, Foo.x))
print()
Good luck,
-Martin
--
Martin A. Brown
http://linux-ip.net/
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Re: [Tutor] Looking for some direction
On 12/05/19 7:59 PM, Alan Gauld via Tutor wrote: On 12/05/2019 00:24, David L Neil wrote: "3 consoles": what is the purpose of each? (my first reaction stemmed from many editors including a built-in console) One for vim, yes - that 'replaces' the window/app running an IDE/GUI-based editor. * One for the Python interpreter * One for an OS shell used for running/testing the app plus any miscellaneous Unixy type things I need to do (sed/grep/awk/git etc). Interestingly, I split these into two - my laziness for running/testing is 'Save, Alt-Tab, Up-arrow, Enter' which would be 'ruined' by using the cmdLN for anything else. I might even 'raise' your bid, by adding a third terminal here - when needing to ssh into a VPS or other remote m/c. I'll usually also have a web browser for reading documentation if necessary, although that's mostly done in the interpreter using dir()/help(). +1 (to make it 'worse', I have two web browsers open - plain-Firefox for 'ordinary browsing' and the FF Development Edition for, well, development work. Yes, that habit probably came out of testing web stuff in multiple browsers, but now the DE is where I cruise the PSL docs, etc, as a de-facto separation-of-concerns in my mind. Alt-Tab and the X cut 'n paste mechanism provides enough integration between windows. Very handy! * > One for the Python interpreter * I also do this, all-the-time. My youngest/new grad colleague observing this last week, was most puzzled. He felt it was 'double-handling' because "most ideas could/should be hashed-out in TDD design" cf 'code experimentation'. Will be interesting to see if he takes-on the idea, or continues to tease 'the old boy'... (any comment if this is my failing to (fully) appreciate TDD philosophy?) I'm using Gnome Terminal under Fedora (Linux). This allows multiple terminals in tabs (and thus Ctrl-Tab rapid-switching). However, it irritates me that whilst I can set "profiles" for particular purposes; there does not seem to be a way to save a 'session'. Thus each time Terminal re-starts, I have to re-build each terminal, manually. (suggestions of other similar tools would be most welcome) I'm also conscious of advising the OP on IDEs/editors: in that I am currently using Sublime Text but find the "build" mechanism quite alien to Python (HTML, CSS, JS, etc - but not Rust!). Similarly, I need to learn more about using ST's built-in terminal (preferably at full-size rather than a few lines at the bottom of the editing window). That might cut-down on one concurrent terminal... (similarly, am open to suggestions for improving Python dev using ST) Thanks for your feedback! -- Regards =dn ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Collating date data from a csv file
Hi David, Firstly, thank you for your reply. One condition of my agreeing to undertake PAT was that I got a PAT machine that stored the data, as I am better at programming than paperwork! I have a Megger PAT 420 which provides a data backup to a USB stick, and thence transfer to my laptop, which is network connected a dual HDD system (Buffalo), which automatically copies the main HDD to the slave HDD. I found out by accident that the Megger PAT 420 data backup is actually an SQLite database, so that is my route for access. Having played with Python on Raspberry Pi's, I thought I would explore Python for data processing, and now, I have a set of programs which extract SQLite, to 'csv' then collate/process this data and produce a multi-page ODS spreadsheet document, which lists tests by location. I also have an application which extracts appliances requiring testing within a +/- 30 day window, so I have a target for testing. My biggest problem is locating kit, and keeping up with removals/disposals and new acquisitions, but the guys are getting a bit better at communication! I thought it would be useful to the 'management' to have a handle on progress, and stats on tested/new/disposed, etc, hence the latest question. I convert the datetimestamp to Gregorian ordinal date, as this is easier to use in accessing the resulting 'defaultdict', do the counting and then convert the date back to something comprehensible for writing to an ODS spreadsheet. Having seen todays posts I am going to look at wxPython, as a front-end (and possibly display?) Thank you for your consideration Dave On 12/05/2019 04:20, David L Neil wrote: Hi Dave, I also volunteer to do PAT safety testing during my "20% time". Clambering around Snowdonia as a boy, I eschewed* the Rheilffordd yr Wyddfa/SMR in favor of shanks' pony... * OK, I was made to...! For the good of my soul??? On 9/05/19 8:04 AM, Dave Hill wrote: I have a csv file which details the results of equipment tests, I carry out PAT testing as a volunteer at a heriatge railway in N. Wales. I want to extract how many items were tested on each test day. So far I have generated a List of test dates, but I am now stalled at how to efficiently count numbers tested on each date. Can I have a list of tuples, where one item is the date and the second the count? or is there a better construct? Thanks in advance, Dave For completeness, I have listed below an extract from a target file, where the 10 digit number is the UNIX timestamp 182 1515001232 Toaster 13 2000 1 183 1515001259 Contact Grill 13 2000 1 245 1515001367 3G Cube Adaptor 13 0 1 246 1515001396 13A IEC Lead 5 0 1 248 1515001415 Worktop Light 3 30 1 420 1515001440 Fly killer 0 0 1 424 1515001461 Dairy fridge 13 0 1 427 1513277293 Fire 13 0 1 429 1515001489 Toaster Avanti 13 0 1 When you say "target file", is this coming off the tester via a link cable to your PC, or are you capturing by hand to a spreadsheet? A tactic which many people 'miss' is that a workbook may contain multiple spreadsheets, and that the data on one spreadsheet may be auto-magically 'copied' onto another. Thus if the above is data coming off the PAT into one spreadsheet, I would immediately create a more meaningful sheet, 'for human consumption', which has column headings and converts (re-formats) the timestamp into a readable date (as suggested elsewhere), but is otherwise pretty-much a direct copy. We now have a sheet used for data capture/computer processing and something separate (and prettier) as a report/presentation for people. From the spec, above, we are only interested in the date. Remember that considering the whole timestamp only makes life confusing. So convert them (only) to dates. These can be strings because Python compares strings as easily as dates! The time component could be retained if sequence (of testing) might be important. The sad reality is that a daily count could be accomplished in either LO-Writer or MS-Excel. No reason why you shouldn't use Python though. (Assuming that the data appears in (forward or reverse) date sequence) Read-in the data sheet/CSV file, row-by-row, taking note of the date of the first data-entry, and starting to count from one. Then increment for each row where the date matches. When the dates don't match, report, reset the counter, and note the new date. How will you lay-out and present this report? Another spreadsheet? Screen? Paper? When you say "count numbers tested on each date", the above method will let you know a (single) daily total of tests-performed. Did you (also) mean that you want to track how many of tests were performed within categories of devices, eg how many toasters on the one day? In which case, furth
[Tutor] What is this code doing? What is it?
We're beginners trying to learn Python and have this sample code:
https://github.com/PySimpleGUI/PySimpleGUI/blob/master/ProgrammingClassExamples/Win10%20versions/2a.%20PSG%20(checkbox%20and%20radiobuttons)%20-%20Copy.py
There is a section of code that has this line::
result = str(' Cost: ' + '${:.2f}'.format(cost))
But I don't understamd what the curly brace part is actually doing:
{:}
'${:.2f}'
I think the 2f means to use 2 decimal places...but what does the rest of
this do?
..curly braces apparenly are for dictionaries...but I don't get how this is
a dictionary..or what this {:} command is actually doing?
Thanks for any clues or links to an easy to understand tutorial or
something on this feature.
- Matt
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Re: [Tutor] Looking for some direction
On 12/05/2019 10:15, David L Neil wrote: > Interestingly, I split these into two - my laziness for running/testing > is 'Save, Alt-Tab, Up-arrow, Enter' which would be 'ruined' by using the > cmdLN for anything else. In a bash shell I use Ctr-R (for reverse search) and hit py to run the last python command. So for me its Alt-Tab, Cmd-R, py 2 characters extra and I get to use the OS for whatever I like in between... :-) -- 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 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] cython and threads, and feedparser
Hello! After a day of various attempts yesterday, I managed to get cython installed on my windows 10 machine. Allow me to prefix this by saying, if there is somewhere else I should put this, II'M SORRY! So I ran cython on my python project, and it worked fine, there was one error about an int, which I have put at the end of this document. In summary though I don't think it has any relevance, might be me though. Here's the problem. In my program, when you load a new feed, the program launches a separate thread for using feedparser to download the rss feed, like this: def loadfeed(feed): # do the feed loading code here # play a sound to say the feed was loaded the loadfeed function is called through the threading module. I put some print statements in, to establish what is going on in cython. According to what I see, it launches the thread fine, it starts, and then it gets to this line: newfeed=feedparser.parse(url) And just, stops. I admit, it could be a speed problem, as I've not had the patients to let it run past about a minute, but in the normal, uncythonised python code, it runs in between 1 and 5 seconds, based on size of feed. It doesn't error, it just acts like it has frozen. The thread doesn't disappear, because the little status checker I have set up to keep an eye on threads within the program says it is still running, it just... seems not to. I know this because, after the line above, I then have: print '2' Which it never does. I was wondering if there is a common cython... thing, I have missed here, where you have to compile feedparser separately? not at all? or something. My worry is not speed, in this instance, 1 to 5 seconds is fine, all things considered and it being in a separate thread... I'm unworried at those timings. My aim with cython was a simple, but nice enough, layer of protection That being said, in my research I had read about the gil? Or something similar to do with only one python thread running at any one time in cython? I admit to not understanding this, though. Any explanations anyone can offer here would be greatly appreciated. Thank you very much. A confused Nate. Compilation: running build_ext cythoning rss.py to rss.c building 'rss' extension C:\Users\natha\AppData\Local\Programs\Common\Microsoft\Visual C++ for Python\9.0\VC\Bin\cl.exe /c /nologo /Ox /MD /W3 /GS- /DNDEBUG -Ic:\python2732\include -Ic:\python2732\PC /Tcrss.c /Fobuild\temp.win32-2.7\Release\rss.obj /openmp rss.c rss.c(6931) : warning C4047: '=' : 'int' differs in levels of indirection from 'PyObject *' C:\Users\natha\AppData\Local\Programs\Common\Microsoft\Visual C++ for Python\9.0\VC\Bin\link.exe /DLL /nologo /INCREMENTAL:NO /LIBPATH:c:\python2732\libs /LIBPATH:c:\python2732\PCbuild /LIBPATH:c:\python2732\PC\VS9.0 /EXPORT:initrss build\temp.win32-2.7\Release\rss.obj "/OUT:C:\Users\natha\Dropbox\coding projects\python\luna rss\rss.pyd" /IMPLIB:build\temp.win32-2.7\Release\rss.lib /MANIFESTFILE:build\temp.win32-2.7\Release\rss.pyd.manifest Creating library build\temp.win32-2.7\Release\rss.lib and object build\temp.win32-2.7\Release\rss.exp C:\Users\natha\AppData\Local\Programs\Common\Microsoft\Visual C++ for Python\9.0\WinSDK\Bin\mt.exe -nologo -manifest build\temp.win32-2.7\Release\rss.pyd.manifest "-outputresource:C:\Users\natha\Dropbox\coding projects\python\luna rss\rss.pyd;2" ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Collating date data from a csv file
On 12/05/2019 11:27, Dave Hill wrote: > I found out by accident that the Megger PAT 420 data backup is actually > an SQLite database, so that is my route for access. Having played with > Python on Raspberry Pi's, I thought I would explore Python for data > processing, and now, I have a set of programs which extract SQLite, to > 'csv' then collate/process this data and produce a multi-page ODS > spreadsheet document, which lists tests by location. I also have an > application which extracts appliances requiring testing within a +/- 30 > day window, so I have a target for testing. You could do it all in native SQLite SQL of course. You can tell sqlite to output its results in Excel CSV format and to a file rather than (or in addition to) stdout. So you can write a standard query and have it generate your Excel readable file directly. You can then automate that as a batch job in the OS... Assuming you run the same reports regularly. Much as I love Python sometimes the native tools are even better... -- 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 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What is this code doing? What is it?
On 12/05/2019 12:31, Matthew Polack wrote:
> result = str(' Cost: ' + '${:.2f}'.format(cost))
>
> But I don't understamd what the curly brace part is actually doing:
> ..curly braces apparenly are for dictionaries...but I don't get how this is
> a dictionary..or what this {:} command is actually doing?
Curly braces inside a string are nothing to do with dictionaries or
sets(which also use them).
They are placeholders for inserted data using the format() string
method. Search the docs for string formatting, you will find a page on
the subject with many examples. (or you could read the "Simple
Sequences" topic in my tutorial - about half way down - see below)
There is another, older style of formatting that uses % characters
instead of {}. You will see both styles used regularly in Python
code. Some folks prefer one, some the other.
They are both very powerful ways of constructing output strings with
data inserted. {} and format() has a few extra tricks once you get
into advanced uses, but % style does most of the same things (and
has the advantage of being used in other languages too so you only
need to remember one style!).
--
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
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Re: [Tutor] Local variable look up outside the function and method
On Sun, May 12, 2019 at 8:05 AM Arup Rakshit wrote:
>
> In the following the function, x is reachable outside the scope of foo
> function.
>
> In [1]: x = 10
>
> In [2]: def foo():
>...: return x
>...:
>
> In [3]: print(foo())
> 10
To what the others have said I wish to point out that if x is
reassigned _inside the function_ x's scope is now local inside the
function while x also still has a module scope. Consider:
3.6.8: x = 10
3.6.8: def foo():
... x = 5
... print("In foo x =", x)
...
3.6.8: foo()
In foo x = 5
3.6.8: print("In module scope, x =", x)
In module scope, x = 10
boB
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Re: [Tutor] Looking for some direction
On Sun, May 12, 2019 at 1:05 PM David L Neil wrote: > I'm using Gnome Terminal under Fedora (Linux). This allows multiple > terminals in tabs (and thus Ctrl-Tab rapid-switching). However, it > irritates me that whilst I can set "profiles" for particular purposes; > there does not seem to be a way to save a 'session'. Thus each time > Terminal re-starts, I have to re-build each terminal, manually. > > (suggestions of other similar tools would be most welcome) I may be mistaken, but I think that a terminal multiplexer like tmux (https://github.com/tmux/tmux/wiki) is capable of session management. I have no personal use of tmux, but have been intrigued enough about others referring to it that eventually I will get around to seriously checking it out. -- boB ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looking for some direction
On Sun, May 12, 2019 at 5:19 PM boB Stepp wrote: > > On Sun, May 12, 2019 at 1:05 PM David L Neil > wrote: > > > I'm using Gnome Terminal under Fedora (Linux). This allows multiple > > terminals in tabs (and thus Ctrl-Tab rapid-switching). However, it > > irritates me that whilst I can set "profiles" for particular purposes; > > there does not seem to be a way to save a 'session'. Thus each time > > Terminal re-starts, I have to re-build each terminal, manually. > > > > (suggestions of other similar tools would be most welcome) > > I may be mistaken, but I think that a terminal multiplexer like tmux > (https://github.com/tmux/tmux/wiki) is capable of session management. > I have no personal use of tmux, but have been intrigued enough about > others referring to it that eventually I will get around to seriously > checking it out. Actually, tmux is starting to look more and more interesting. David, I think you might this helpful. I am currently looking at an introduction to tmux by a Stack Overflow developer. This article is at https://www.hamvocke.com/blog/a-quick-and-easy-guide-to-tmux/ (There was a link to this on the tmux wiki I sent out a link to earlier.) I think I may start playing around with this! -- boB ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looking for some direction
On 12May2019 17:19, boB Stepp wrote: On Sun, May 12, 2019 at 1:05 PM David L Neil wrote: I'm using Gnome Terminal under Fedora (Linux). This allows multiple terminals in tabs (and thus Ctrl-Tab rapid-switching). However, it irritates me that whilst I can set "profiles" for particular purposes; there does not seem to be a way to save a 'session'. Thus each time Terminal re-starts, I have to re-build each terminal, manually. (suggestions of other similar tools would be most welcome) I may be mistaken, but I think that a terminal multiplexer like tmux (https://github.com/tmux/tmux/wiki) is capable of session management. I have no personal use of tmux, but have been intrigued enough about others referring to it that eventually I will get around to seriously checking it out. Tmux is great, but I mostly use it for persistent sessions. It has facilities for running multiple panes in one terminal, which could be useful for remote sessions; locally I just use multiple panes in my terminal emulator, and in fact just multiple local panes connected to remote sessions anyway. I do use tmux panes in email though: I invoke mutt in a tmux session and replies start in a subpane, with mutt's index view in the upper (smaller) pane. But otherwise it is almost all persistent (and named) sessions. Now, I am spoilt: on a Mac I have access to iTerm3, which does: multiple tabs _and multiple panes and subpanes. My usual coding layout is a terminal in the left half of the screen running vim (with, usually, two _vim_ windows in it, vertically split). Often, that window gets a horizontal split, with a short and wide terminal pane below the editors, where I have a shell. The right hand half is antoher terminal, usually split intovarious panes, often 2 more evenly split. FOr shells and Python interpreters. But a really good terminal emulator is an outstanding tool. And iTerm3 seems to outshine everything else (Mac only alas - I'd like to find a food X11 equivalent - everything I've tried is deficient). Tabs and multiple panes is hugely flexible. It also has a toggle keystroke to expand a particular pane to the full window for when you want lots of text (diffs, commiting, etc). So unlike Alan, since it is all one Mac app (iTerm3), there's no Alt-TAB to switch apps, and since it does focus-follows-mouse cut/paste is very fast (iTerm3 has a mode like most X11 apps: select implicitly copies, so no Cmd-C copy keystroke for me either). Cheers, Cameron Simpson ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Looking for some direction
On 12/05/2019 23:19, boB Stepp wrote: > I may be mistaken, but I think that a terminal multiplexer like tmux > (https://github.com/tmux/tmux/wiki) is capable of session management. > I have no personal use of tmux, but have been intrigued enough about > others referring to it that eventually I will get around to seriously > checking it out. Me too. its been on my "must check that out" list for years! But I really must -- 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 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What is this code doing? What is it?
On 5/12/19, Alan Gauld via Tutor wrote:
>
> They are both very powerful ways of constructing output strings with
> data inserted. {} and format() has a few extra tricks once you get
> into advanced uses, but % style does most of the same things (and
> has the advantage of being used in other languages too so you only
> need to remember one style!).
IMHO, given the choice of learning only one, learn the newer
curly-brace string formatting system. It's extensible since it's based
on a __format__ special method that a type (i.e. class) can override.
Take the Decimal type, for instance. By default it supports 28 digits
of precision. For example:
>>> from decimal import Decimal
>>> n = Decimal('0.12340567891234056789123405669') * 10
>>> n
Decimal('1.234056789123405678912340567')
Decimal implements the __format__ special method with its own
implementation of the "f" format specifier, which faithfully renders
the value as a string.
>>> '{:0.27f}'.format(n)
'1.234056789123405678912340567'
We can also use this directly with the built-in format() function in Python 3:
>>> format(n, '0.27f')
'1.234056789123405678912340567'
On the other hand, if we use a string's percent formatting, its "f"
format specifier has a fixed implementation that first converts a
number to a Python float, as opposed to delegating the string
conversion to the object itself.
>>> float(n)
1.2340567891234058
>>> '%0.27f' % n
'1.234056789123405772912178691'
As you can see in the formatted output, everything after
"1.234056789123405" is wrong. This is because a CPython float is
implemented as a C double-precision value, which only has about 16
decimal digits of precision.
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