Thanks for your reply.But the answer is not I except, I will show you some examples to explain what result I except: @contextmanagerdef cm(): print('open file') yield print('close file')with cm(): 1/0 If I use a contextmanager ,I except it can help me to close the file anytime,even raise an error,but if I define a function with @contextmanager like the example which I have showed for you, it will never print('close file') I can only modify it like this:@contextmanagerdef cm(): try: print('open file') yield except Exception as e: print('Error',e) finally: print('close file') It is not friendly for us to use it, so I modify the contextlib to fix it,you can catch it from the e-mail attachment.It's in the line 79 and line 97---------------------------------------------------------------------- 发件人：python-ideas-request@python.org 收件人：python-ideas@python.org 主题：Python-ideas Digest, Vol 146, Issue 13 日期：2019年01月06日 01点05分 Send Python-ideas mailing list submissions to python-ideas@python.org To subscribe or unsubscribe via the World Wide Web, visit https://mail.python.org/mailman/listinfo/python-ideas or, via email, send a message with subject or body 'help' to python-ideas-request@python.org You can reach the person managing the list at python-ideas-owner@python.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Python-ideas digest..." Today's Topics: 1. Re: Make the @contextmanager of contextlib to be a real contextmanager (Serhiy Storchaka) 2. Re: Fixed point format for numbers with locale based separators (?ukasz Stelmach) ---------------------------------------------------------------------- Message: 1 Date: Sat, 5 Jan 2019 16:45:34 +0200 From: Serhiy Storchaka <storchaka@gmail.com> To: python-ideas@python.org Subject: Re: [Python-ideas] Make the @contextmanager of contextlib to be a real contextmanager Message-ID: <q0qfqd$q1q$1@blaine.gmane.org> Content-Type: text/plain; charset=UTF-8; format=flowed 05.01.19 14:52, Moon?sun ????:

As we know,when we import the module--'contextlib',we can use the decorator '@contextmanager' and keyword ?yield? to make a 'instance' of Class '_GeneratorContextManager' in 'contextlib' module,then we can use it like: with 'instance' as 'xx': ? ? 'code block' ? ? pass But there is a little bug,when the code block raise a error,the instance cannot run the code which after the keyword 'yield'. This is not a bug. Consider the following example: @contextmanager def cm(): try: yield except BaseException as err: print('Fail:', err) raise else: print('Success') with cm(): 1/0 What result would you expect? Test it with the stdlib implementation and with your implementation.

On Fri, Jan 04, 2019 at 03:57:53PM +0100, ?ukasz Stelmach wrote:

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Hi,

I would like to present two pull requests[1][2] implementing fixed point presentation of numbers and ask for comments. The first is mine. I learnt about the second after publishing mine.

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In the application I want to create I am going to present users numbers ranging up to 3 orders of magnitude and I (my users) want them to be presented consistently with regards to number of decimal digits AND I want to conform to rules of languages of my users. And I would like to avoid the exponent notation by all means. The pint[1] library I use, implements formatting of physical quantities using the format()/__format__ code. As far as I can tell my patch for Python is shorter and more straightforward than a patch for pint to use locale.format(). Because the "g" based "n" formatter has been present since the advanced string formatting was described in PEP-3101, I think it is necessary to add the "m" formatter based on "f". The advanced string formatting facility in Python is very convenient and programmers shouldn't forced to use locale.format() like this "The total length of {} sticks is {} meters.".format(n_sticks, locale.format(".2f", l_sticks)) instead of "The total length of {} sticks is {:.2f} meters.".format(n_sticks, l_sticks) In other words, what is the new feature you hope to have excepted? Explain the intention and the API (the interface). The implementation is

Before I look at the implementation, can you explain the functional requirements please? As I stated in the original message below the table: the least important part :-) I wish to add a new formatter "m" for float/complex/decimal numbers, which behaves like the existing "f", but uses the decimal separator from

Message: 2 Date: Sat, 05 Jan 2019 16:41:20 +0100 From: ?ukasz Stelmach <steelman@post.pl> To: Steven D'Aprano <steve@pearwood.info> Cc: python-ideas@python.org Subject: Re: [Python-ideas] Fixed point format for numbers with locale based separators Message-ID: <87y37z9knz.fsf%steelman@post.pl> Content-Type: text/plain; charset="utf-8" Steven D'Aprano <steve@pearwood.info> writes: the locale database. There is "n" formmatter which behaves like "g" but it does not fit my needs.

[...]

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Formatting 1.23456789 * n (LC_ALL=3Dpl_PL.UTF-8) | n | ".2f" | ".3n" | |---+----------+----------| | 1 | 1.23 | 1,23 | | 2 | 12.35 | 12,3 | | 3 | 123.46 | 123 | | 4 | 1234.57 | 1,23e+03 |

I'm afraid I cannot work out what that table means. You say "Formatting 1.23... * n" (multiplying by n) but the results shown aren't multiplied by n=2, n=3, n=4 as the table suggests.

Can you show what Python code you expect will produce the expected output? for n in range(1,5): print("| {} | {:8.2f} | {:8.3n} |".format(n,1.23456789 * 10**n, 1.23456789 * 10**n)) [1] http://pint.readthedocs.io/ -- By?o mi bardzo mi?o. --- Rurku. --- ... ?ukasz< --- To dobrze, ?e mnie s?uchasz.