Re: Finding good documentation for gpiod
E > On 3 Sep 2023, at 22:49, Chris Green via Python-list > wrote: > > Mostly I am managing to get things to work as I want but better > documentation of gpiod would be a great help. Ask the author? https://github.com/aswild/python-gpiod Maybe read the source code for hints? Barry -- https://mail.python.org/mailman/listinfo/python-list
Re: Forward References
On 2023-09-03 21:43, Jonathan Gossage via Python-list wrote: I am attempting to use forward references in my program and I am failing. This also does not work with the older way of putting the name of a class as a string. Here is some sample code: from __future__ import annotations from dataclasses import dataclass from typing import TypeAlias ColorDef: TypeAlias = RGB | int | str @dataclass(frozen=True, slots=True) class RGB(object): Can anyone suggest how I should fix this without reversing the statement order? pass The usual way to deal with forward type references is to use a string literal, i.e. 'RGB', but that doesn't work with '|', so use typing.Union instead: from typing import TypeAlias, Union ColorDef: TypeAlias = Union['RGB', int, str] -- https://mail.python.org/mailman/listinfo/python-list
Re: iterations destroy reversed() results
On Mon, 4 Sept 2023 at 07:44, Pierre Fortin via Python-list wrote: > > Hi, > > reversed() results are fine until iterated over, after which the > results are no longer available. This was discovered after using > something like this: > > rev = reversed( sorted( list ) ) > sr = sum( 1 for _ in rev ) > # rev is now destroyed > > So reversed() results can only be iterated once unlike sorted(), etc... reversed() is like iter(), and should be used the same way: for item in reversed(list): If you want to eagerly construct a full reversed list, instead slice the list: list[::-1] ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Passing info to function used in re.sub
On 9/3/2023 12:10 PM, Jan Erik Moström via Python-list wrote: I'm looking for some advice for how to write this in a clean way I want to replace some text using a regex-pattern, but before creating replacement text I need to some file checking/copying etc. My code right now look something like this: def fix_stuff(m): # Do various things that involves for info # that what's available in m replacement_text = m.group(1) + global_var1 + global_var2 return replacement_text and the call comes here global_var1 = "bla bla" global_var2 = "pff" new_text = re.sub(im_pattern,fix_stuff,md_text) The "problem" is that I've currently written some code that works but it uses global variables ... and I don't like global variables. I assume there is a better way to write this, but how? = jem There are two things to keep in mind here, I think. First, in Python a "global" variable is really module-level, so variables specific to one module seem fine and are common practice. Second, the way you have written this example, it looks like these module-level "variables" are in effect constants. In other words, they are just shorthand for specific declared quantities. If this is so, then it makes even more sense to define them as module-level objects in the module that needs to use them. If you still don't want to use them as "global" in your module, then define them in a separate module and import them from that module. -- https://mail.python.org/mailman/listinfo/python-list
Re: iterations destroy reversed() results
On 9/1/2023 12:15 PM, Pierre Fortin via Python-list wrote: Hi, reversed() results are fine until iterated over, after which the results are no longer available. This was discovered after using something like this: rev = reversed( sorted( list ) ) sr = sum( 1 for _ in rev ) # rev is now destroyed So reversed() results can only be iterated once unlike sorted(), etc... reversed() is an iterator these days: >>> l1 = [1, 2, 3] >>> rev = reversed( sorted( l1 ) ) >>> type(rev) > -- https://mail.python.org/mailman/listinfo/python-list
Re: iterations destroy reversed() results
It is by design. `sorted` returns a list, while `reversed` returns an iterator. Iterators are exhaust-able, and not reusable. So be mindful of this and if you are going to "re-use” the sequence returned by iterator, convert it to list first. Have a look at `itertools` library, which contains a lot of such functions and many good recipes on achieving various things elegantly using iterators. > On 1 Sep 2023, at 19:15, Pierre Fortin via Python-list > wrote: > > Hi, > > reversed() results are fine until iterated over, after which the > results are no longer available. This was discovered after using > something like this: > > rev = reversed( sorted( list ) ) > sr = sum( 1 for _ in rev ) > # rev is now destroyed > > So reversed() results can only be iterated once unlike sorted(), etc... > > Script to illustrate the issue: > /tmp/rev: > orig = [ 'x', 'a', 'y', 'b', 'z', 'c' ] > co = sum( 1 for _ in orig ) > print( 'orig', orig, co ) > # reversing > rev = reversed(orig) > print( 'before iteration:', [ x for x in rev ] ) > # list comprehension was an iteration over 'rev' > print( 'after iteration:', [ x for x in rev ] ) > # how this was discovered... > orig = [ 'x', 'a', 'y', 'b', 'z', 'c' ] > rev = reversed(orig) > cr = sum( 1 for _ in rev ) > print( 'after sum():', [ x for x in rev ] ) > > which produces: > > $ python /tmp/rev > orig ['x', 'a', 'y', 'b', 'z', 'c'] 6 > before iteration: ['c', 'z', 'b', 'y', 'a', 'x'] > after iteration: [] > after sum(): [] > > Regards, > Pierre > -- > https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
Finding good documentation for gpiod
I am using the gpiod package for manipulating GPIO inputs/outputs on a Beaglebone Black SBC (like a Raspberry Pi but with more flexible I/O). Mostly I am managing to get things to work as I want but better documentation of gpiod would be a great help. For example, when one has found an I/O pin (a 'line' in GPIO parlance) that one wants to use one has to 'request' it using the Line.request() method. The help for this is as follows:- Help on method_descriptor: request(...) request(consumer[, type[, flags[, default_val]]]) -> None Request this GPIO line. consumer Name of the consumer. type Type of the request. flags Other configuration flags. default_val Default value of this line. Note: default_vals argument (sequence of default values passed down to LineBulk.request()) is still supported for backward compatibility but is now deprecated when requesting single lines. Which is pretty good **except** that I can't find a proper description of the parameters anywhere, i.e. there's nowhere that even tells me what types of values/objects the parameters are. At the end of the gpiod.Line section of the help there is this:- | ACTIVE_HIGH = 1 | | ACTIVE_LOW = 2 | | BIAS_AS_IS = 1 | | BIAS_DISABLE = 2 | | BIAS_PULL_DOWN = 4 | | BIAS_PULL_UP = 3 | | DIRECTION_INPUT = 1 | | DIRECTION_OUTPUT = 2 Which **might** be appropriate values for 'type' or 'flags' but there doesn't seem to be any way of knowing. Am I missing something very obvious somewhere? Is there a 'standard' way of finding out parameter information? It may well be that I'm simply banging up against the limit of what documentation is available, I have managed to get code working OK. It's just that I'd be happier if I really know what I was doing! :-) -- Chris Green · -- https://mail.python.org/mailman/listinfo/python-list
iterations destroy reversed() results
Hi, reversed() results are fine until iterated over, after which the results are no longer available. This was discovered after using something like this: rev = reversed( sorted( list ) ) sr = sum( 1 for _ in rev ) # rev is now destroyed So reversed() results can only be iterated once unlike sorted(), etc... Script to illustrate the issue: /tmp/rev: orig = [ 'x', 'a', 'y', 'b', 'z', 'c' ] co = sum( 1 for _ in orig ) print( 'orig', orig, co ) # reversing rev = reversed(orig) print( 'before iteration:', [ x for x in rev ] ) # list comprehension was an iteration over 'rev' print( 'after iteration:', [ x for x in rev ] ) # how this was discovered... orig = [ 'x', 'a', 'y', 'b', 'z', 'c' ] rev = reversed(orig) cr = sum( 1 for _ in rev ) print( 'after sum():', [ x for x in rev ] ) which produces: $ python /tmp/rev orig ['x', 'a', 'y', 'b', 'z', 'c'] 6 before iteration: ['c', 'z', 'b', 'y', 'a', 'x'] after iteration: [] after sum(): [] Regards, Pierre -- https://mail.python.org/mailman/listinfo/python-list
Re: Why do I always get an exception raised in this __init__()?
Alan Gauld wrote:
> On 31/08/2023 22:15, Chris Green via Python-list wrote:
>
> > class Gpiopin:
> >
> > def __init__(self, pin):
> > #
> > #
> > # scan through the GPIO chips to find the line/pin we want
> > #
> > for c in ['gpiochip0', 'gpiochip1', 'gpiochip2', 'gpiochip3']:
> >
> > chip = gpiod.Chip(c)
> > for l in range(32):
> > line = chip.get_line(l)
> > if pin in line.name():
> > print("Found: ", line.name())
> > return
> > else:
> > raise ValueError("Can't find pin '" + pin + "'")
>
> You don't store the line anywhere.
> You need to use self.line
> self.line = chip.get_line(l)
> if pin...
>
> > def print_name(self):
> > print (self.line.name())
> >
> > def set(self):
> > self.line.set_value(1)
> >
> > def clear(self):
> > self.line.set_value(0)
>
> As you do here.
>
Yes, OK, absolutely. However that wasn't my original rather basic
problem which was, as I said, that I wasn't running the code I was
looking at.
The above was just a quick hack from some even cruder code doing the
same job, trying to develop it into something better and more general.
It's all on a headless Beaglebone Black (bit like a Raspberry Pi) so
I'm doing everything via multiple ssh connections and sometimes this
results in "the left hand not knowing what the right hand is doing"!
--
Chris Green
·
--
https://mail.python.org/mailman/listinfo/python-list
Forward References
I am attempting to use forward references in my program and I am failing. This also does not work with the older way of putting the name of a class as a string. Here is some sample code: from __future__ import annotations from dataclasses import dataclass from typing import TypeAlias ColorDef: TypeAlias = RGB | int | str @dataclass(frozen=True, slots=True) class RGB(object): Can anyone suggest how I should fix this without reversing the statement order? pass -- Jonathan Gossage -- https://mail.python.org/mailman/listinfo/python-list
Re: Passing info to function used in re.sub
On 3 Sep 2023, at 19:13, MRAB via Python-list wrote: > You could use pass an anonymous function (a lambda) to re.sub: Of course !! Thanks. = jem -- https://mail.python.org/mailman/listinfo/python-list
Re: Passing info to function used in re.sub
On 2023-09-03 17:10, Jan Erik Moström via Python-list wrote: I'm looking for some advice for how to write this in a clean way I want to replace some text using a regex-pattern, but before creating replacement text I need to some file checking/copying etc. My code right now look something like this: def fix_stuff(m): # Do various things that involves for info # that what's available in m replacement_text = m.group(1) + global_var1 + global_var2 return replacement_text and the call comes here global_var1 = "bla bla" global_var2 = "pff" new_text = re.sub(im_pattern,fix_stuff,md_text) The "problem" is that I've currently written some code that works but it uses global variables ... and I don't like global variables. I assume there is a better way to write this, but how? You could use pass an anonymous function (a lambda) to re.sub: def fix_stuff(m, var1, var2): # Do various things that involves for info # that what's available in m replacement_text = m.group(1) + var1 + var2 return replacement_text global_var1 = "bla bla" global_var2 = "pff" new_text = re.sub(im_pattern, lambda m, var1=global_var1, var2=global_var2: fix_stuff(m, var1, var2), md_text) Or, if you prefer a named function, define one just before the re.sub: def fix_stuff(m, var1, var2): # Do various things that involves for info # that what's available in m replacement_text = m.group(1) + var1 + var2 return replacement_text global_var1 = "bla bla" global_var2 = "pff" def fix_it(m, var1=global_var1, var2=global_var2): return fix_stuff(m, var1, var2) new_text = re.sub(im_pattern, fix_it, md_text) -- https://mail.python.org/mailman/listinfo/python-list
Passing info to function used in re.sub
I'm looking for some advice for how to write this in a clean way I want to replace some text using a regex-pattern, but before creating replacement text I need to some file checking/copying etc. My code right now look something like this: def fix_stuff(m): # Do various things that involves for info # that what's available in m replacement_text = m.group(1) + global_var1 + global_var2 return replacement_text and the call comes here global_var1 = "bla bla" global_var2 = "pff" new_text = re.sub(im_pattern,fix_stuff,md_text) The "problem" is that I've currently written some code that works but it uses global variables ... and I don't like global variables. I assume there is a better way to write this, but how? = jem -- https://mail.python.org/mailman/listinfo/python-list
[Python-announce] [RELEASE] pyspread 2.2.2
pyspread 2.2.2 == This is a bugfix release. Bug fixes: * pip install fixed by replacing deprecated setup.py option `requires` with `install_requires` * Shebang removed from desktop file About pyspread == Pyspread is a non-traditional spreadsheet that is based on and written in the programming language Python. The goal of pyspread is to be the most pythonic spreadsheet application. Pyspread is free software. It is released under the GPL v3. Project website: https://pyspread.gitlab.io/ Download page: https://pypi.org/project/pyspread/ Signature for tarball: https://gitlab.com/pyspread/downloads/-/raw/master/releases/pyspread-2.2.2.tar.gz.asc?inline=false Source code: https://gitlab.com/pyspread/pyspread Dependencies Mandatory: * Python (≥ 3.6) * numpy (>=1.1) * PyQt5 (≥ 5.10, requires PyQt5.Svg) * setuptools (>=40.0) * markdown2 (>= 2.3) Recommended: * matplotlib (>=1.1.1) * pyenchant (>=1.1) * pip (>=18) * python-dateutil (>= 2.7.0) * py-moneyed (>=2.0) * rpy2 (>=3.4) * plotnine (>=0.8) * libvoikko (>=4.3) * nuspell (>=5.1) * hspell (>= 1.4) * ggplot2 (>=3.4) For building the apidocs with Sphinx see apidocs/requirements.txt Enjoy Martin ___ Python-announce-list mailing list -- python-announce-list@python.org To unsubscribe send an email to python-announce-list-le...@python.org https://mail.python.org/mailman3/lists/python-announce-list.python.org/ Member address: arch...@mail-archive.com
