Re: Is it possible to inheret a metaclass.

[Pieter van Oostrum]

Pieter van Oostrum  writes:

> Your Pardon is not a class, it is a function. Class A is created by
> type(cls, *args), so 'type' is the metaclass of A, and therefore also of
> B.
> Creation of B does not call Pardon.

With a class it *does* work:

In [74]: class Pardon(type):
 ... def __init__(cls, *args):
 ... print("Calling Pardon with", cls)

In [75]: class A(metaclass=Pardon): pass
Calling Pardon with 

In [76]: class B(A): pass
Calling Pardon with 

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Re: RFC: For Loop Invariants

[Rhodri James]

On 10/04/2020 21:44, Elliott Dehnbostel wrote:

Hello Everyone,

I've also posted this to the python-ideas mailing list, but I thought to
post here as well for a more general audience.

If I've done this incorrectly, please let me know so that I can
improve/revise. I'm new to the Python community and quite enjoy the more
functional features of Python 3, but have I have a peeve about it. I'd like
to propose and discuss the following enhancement to Python 3:

*Consider the following trivial for-loop:*

chars = "abcaaabkjzhbjacvb"
seek = {'a','b','c'}
count = 0for a in chars:
  if a in seek:
   count += 1

Gross. Twice nested for a simple count.


a) I don't personally think that's gross (apart from the missing 
newline, which is just an email artefact I assume).


b) If it's simple like this and you care enough, refactor it as a 
comprehension:


  count = sum(1 for a in chars if a in seek)

It it's not so simple, neither the comprehension nor your proposal are 
going to be as readable as the twice nesting.


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Re: Is it possible to inheret a metaclass.

[Peter Otten]

Antoon Pardon wrote:

> 
> 
> Op 9/04/20 om 18:37 schreef Peter Otten:
>> Antoon Pardon wrote:
>> 
>>> I am experimenting with subclasses that all need the same metaclass as
>>> the base class. Is there a way to make the metaclass be inherited, so
>>> that you don't have to repeat the "metaclass = MetaClass" with every
>>> subclass.
>> 
>> ?
>> 
>> This is not only possible, this is the default:
>> 
>>   >>> class Pardon(type): pass
>> ...
> class A(metaclass=Pardon): pass
>> ...
> class B(A): pass
>> ...
> type(B)
>> 
> 
> Can you explain what is wrong with the code below:
> 
> This produces only: Calling Pardon with A.
> 
> 
> def Pardon(cls, *args):
>  print("Calling Pardon with", cls)
>  return type(cls, *args)
> 
> class A(metaclass=Pardon): pass
> 
> class B(A): pass

As has been pointed out, the problem is the factory function you are using 
instead of a class. One way to look at it:

class Foo: 
pass

def make_foo(): 
return Foo()

foo = make_foo()
assert isinstance(foo, make_foo)

Would you expect the assertion to succeed? Would you expect that foo 
remembers that it has been created by make_foo()? 
No? Then replace the instance with the class, the class with the metaclass.


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Re: RFC: For Loop Invariants

[Terry Reedy]

On 4/10/2020 4:44 PM, Elliott Dehnbostel wrote:


chars = "abcaaabkjzhbjacvb"
seek = {'a','b','c'}
count = 0for a in chars:
  if a in seek:
   count += 1


Why did you repeatly omit the \n after 0?  Please paste code that ran


Gross. Twice nested for a simple count.


Twice indented does not particularly bother me.

> [snip]

*We could do this:*

chars = "abcaaabkjzhbjacvb"
seek = {'a','b','c'}
count = sum([1 for a in chars if a in seek])

However, this changes important semantics by creating an entire new
list before summing.


Unnecessary.  Use a generator comprehension (expression).

sum(1 for a in chars if a in seek)


chars = "abcaaabkjzhbjacvb"
seek = {'a','b','c'}
count = 0  # fixed
for a in chars if a in seek: count += 1


Rejected and rejected again, any mixing of keyword clauses like this 
except in comprehensions.  The sum expression is shorter and only 1 line.


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Terry Jan Reedy

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help me subcorrect

[khuchee]

Sent from Mail for Windows 10

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plead add persian languges

[m. bahrami]

Sent from Mail for Windows 10

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problem in installing

[shina sameeran]

i tried to install python 3.8.2 in my HP windows 8 laptop(core i3). after
installation when i tried to open the programme it shows  window says
modify, repair or uninstall.  it does not work after modify and repair.
please help.


yours sincerely

shina  m j
chennai
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Re: problem in installing

[Souvik Dutta]

You are running the installer instead of the program itself. Try searching
idle from the start menu and run it in that way.

Souvik flutter dev

On Sat, Apr 11, 2020, 8:36 PM shina sameeran 
wrote:

> i tried to install python 3.8.2 in my HP windows 8 laptop(core i3). after
> installation when i tried to open the programme it shows  window says
> modify, repair or uninstall.  it does not work after modify and repair.
> please help.
>
>
> yours sincerely
>
> shina  m j
> chennai
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Re: py2c - an open source Python to C/C++ is looking for developers

[jared . h . lam]

On Monday, July 30, 2012 at 6:27:04 AM UTC-7, manian...@gmail.com wrote:
> I created py2c ( http://code.google.com/p/py2c )- an open source Python to 
> C/C++ translator!
> py2c is looking for developers!
> To join create a posting in the py2c-discuss Google Group or email me!
> Thanks
> PS:I hope this is the appropiate group for this message.

Here is my code from python
import cv2
import numpy as np

img = cv2.imread('c1.pgm',0)
img = cv2.medianBlur(img,5)
cimg = cv2.cvtColor(img,cv2.COLOR_GRAY2BGR)

circles = cv2.HoughCircles(img,cv2.HOUGH_GRADIENT,1,20,
param1=50,param2=30,minRadius=10,maxRadius=60)

circles = np.uint16(np.around(circles))
for i in circles[0,:]:
# draw the outer circle
cv2.circle(cimg,(i[0],i[1]),i[2],(0,255,0),2)
# draw the center of the circle
cv2.circle(cimg,(i[0],i[1]),2,(0,0,255),3)

cv2.imshow('detected circles',cimg)
cv2.waitKey(0)
cv2.destroyAllWindows()
Thanks a bunch
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Re: RFC: For Loop Invariants

[Peter J. Holzer]

On 2020-04-10 15:44:05 -0500, Elliott Dehnbostel wrote:
> *Consider the following trivial for-loop:*
> 
> chars = "abcaaabkjzhbjacvb"
> seek = {'a','b','c'}
> count = 0
> for a in chars:
>  if a in seek:
>   count += 1
> 
> Gross. Twice nested for a simple count.
> 
[...]
> I propose the following enhancement:
> 
> chars = "abcaaabkjzhbjacvb"
> seek = {'a','b','c'}
> count = 0
> for a in chars if a in seek: count += 1

I don't see much of an enhancement here. You save writing one colon and
one newline here. The code itself is exactly the same. If the original
was gross (I don't agree), then this is just as gross.

hp

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   _  | Peter J. Holzer| Story must make more sense than reality.
|_|_) ||
| |   | h...@hjp.at |-- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |   challenge!"


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Getting ReadTimeoutError for tensorflow while deploying python app to Azure Web App

[kargawal . abhishek]

remote: [20:44:36+] Collecting tensorflow==2.1.0

remote: [20:44:36+] Downloading 
tensorflow-2.1.0-cp37-cp37m-manylinux2010_x86_64.whl (421.8 MB)

remote: ...

remote: ...

remote: 
.

remote: WARNING: Retrying (Retry(total=4, connect=None, read=None, 
redirect=None, status=None)) after connection broken by ' 
("HTTPSConnectionPool(host='pypi.org', port=443): Read timed out. (read 
timeout=15)")': /simple/tensorflow-estimator/

remote: [20:51:54+] Collecting tensorflow-estimator==2.1.0

remote: ..

remote: WARNING: Retrying (Retry(total=4, connect=None, read=None, 
redirect=None, status=None)) after connection broken by 
'ReadTimeoutError("HTTPSConnectionPool(host='files.pythonhosted.org', 
port=443): Read timed out. (read timeout=15)")': 
/packages/18/90/b77c328a1304437ab1310b463e533fa7689f4bfc41549593056d812fab8e/tensorflow_estimator-2.1.0-py2.py3-none-any.whl

remote: [20:52:09+] Downloading 
tensorflow_estimator-2.1.0-py2.py3-none-any.whl (448 kB)
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Re: help me subcorrect

[Souvik Dutta]

Did you send a screenshot? If so then understand that this mailing list
does not support photos so you cannot send that. Try giving us a verbal
description. And if you write anything other that the sub then sorry that
is my Gmail's fault.

Souvik flutter dev

On Sat, Apr 11, 2020, 8:32 PM khuchee  wrote:

>
>
> Sent from Mail for Windows 10
>
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