[issue33040] Make itertools.islice supports negative values for start and stop arguments for sized iterable object

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

Now I have thought about it and realized that
it's not suitable for islice.
But there's still a common use case to
drop some elements from the beginning or
ending of a iterable, which is also a main
reason why I wanted islice to support
negative values of start and stop.
So how about adding two functions
``drop_first`` and ``drop_last``
to do such things. They can be implemented
like this, in which way they support
arbitrary iterators::

def drop_first(iterable, n=1):
for _ in range(n):
next(iterable)
for e in iterable:
yield e

def drop_last(iterable, n=1):
dq = deque()
for _ in range(n):
dq.append(next(iterable))
for e in iterable:
dq.append(e)
yield dq.popleft()

--

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue33040>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue12345] Add math.tau

[TitanSnow]

Change by TitanSnow <tttnns1...@gmail.com>:


--
pull_requests: +5816

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue12345>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

For the case of sequential writes to the same file,
I think it’s a invalid use case.
The file can be created or modified by
user or other applications, breaking the assume of
ConfigParser. It’s better to have a method to merge
two ConfigParser objects then writes it into the file
at one time.

--

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

> But I didn't thought that a superfluous final blank line causes any problems. 
> What software has a problem with it?

Currently I have not found a program that has problem with
the superfluous final blank line, and I think there won’t be.

> Removing the final blank line can harm the readability in the case of 
> sequential writes to the same file

Sorry that I have not thought about this.
In this way, the prev patch that adds two new parameters might be better.

> Remind me, why do we care about that extra blank line?

Well, though it seems that that extra blank line won’t cause any problem,
it does not look nice I think, and is different with INI files written
by other applications.

--

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue33040] Make itertools.islice supports negative values for start and stop arguments for sized iterable object

[TitanSnow]

New submission from TitanSnow <tttnns1...@gmail.com>:

``islice()`` does not support negative values for start or stop,
which does not matter for plain iterators.
However, for some cases, we have a sized iterable object
which is not subscriptable, using ``islice()`` makes
code ugly::

d = OrderedDict()
for i in range(10): d[i] = i
dv = d.keys()
# dv is a KeysView which is a sized iterable

# now I wanna get a slice of dv which does not contain the last element
islice(dv, len(dv) - 1)

As it shows, I have to use ``len(dv)`` to get its length.

For sized iterable objects, ``islice()`` could
support negative values for start or stop.
In this way, the above code can be written like this::

islice(dv, -1)

For iterable objects which is not sized,
it could still be not supported::

islice(iter(range(10)), -1)

raises a ValueError as its original behavior.

--
components: Library (Lib)
files: islice.patch
keywords: patch
messages: 313517
nosy: tttnns
priority: normal
severity: normal
status: open
title: Make itertools.islice supports negative values for start and stop 
arguments for sized iterable object
type: enhancement
Added file: https://bugs.python.org/file47475/islice.patch

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue33040>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

If we treat the original behavior as a bug,
it’s much easier to write a patch
that just changes the default behavior
and never outputs a final blank line.

I have looked through the testsuite of it.
It seems that the original author had knew
the final blank line and treat it as
expect result. I’m not sure about it.

--
Added file: https://bugs.python.org/file47474/simple.patch

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

I’m afraid of breaking the backward compatibility.

--

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32930] [help][webbrowser always opens new tab. I want to open in the same tab]

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

Yes, I think so.

Maybe, in a web application, to achieve this,
the way is to use a GUI library then use its
web view widget.

--

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32930>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32930] [help][webbrowser always opens new tab. I want to open in the same tab]

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

Hi Cheryl,

I think you may misunderstand.
What it means is to open URL in
the *same tab*, not *same window*,
which is not described in documentation.

Hi Tommy,

It’s hard to say what is “the same tab”.
Is it the current tab or the tab opened by
last webbrowser.open call?
If the user open a new tab in the opened browser,
then which tab is “the same tab”?

--
nosy: +tttnns

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32930>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

Change by TitanSnow <tttnns1...@gmail.com>:


Removed file: https://bugs.python.org/file47461/bpo-32917.patch

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

Change by TitanSnow <tttnns1...@gmail.com>:


--
pull_requests: +5621
stage:  -> patch review

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue12345] Add math.tau

[TitanSnow]

Change by TitanSnow <tttnns1...@gmail.com>:


--
pull_requests: +5622

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue12345>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

Change by TitanSnow <tttnns1...@gmail.com>:


Removed file: https://bugs.python.org/file47460/final_blank_line.patch

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

Patch updated, included documentation and tests.

--
Added file: https://bugs.python.org/file47461/bpo-32917.patch

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

TitanSnow <tttnns1...@gmail.com> added the comment:

**It's not final newline \n !**

Maybe what I said confused. The "final blank line"
does not mean the "final newline char".
It means an extra blank line after last line.

It might be clearer to represent it in a string::

'[section1]\nkey = value\n\n[section2]\nkey = value\n\n'

It has *two* \n at end. I think it should be only one.

--

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32917] ConfigParser writes a superfluous final blank line

[TitanSnow]

New submission from TitanSnow <tttnns1...@gmail.com>:

``ConfigParser.write()`` writes a superfluous final blank line.

Example::

import configparser
cp = configparser.ConfigParser()
cp['section1'] = {'key': 'value'}
cp['section2'] = {'key': 'value'}
with open('configparser.ini', 'w') as f:
cp.write(f)

The output file 'configparser.ini' will be:: (I added line number)

  1 [section1]
  2 key = value
  3 
  4 [section2]
  5 key = value 
  6 

with a superfluous final blank line.


Compare to ``GLib.KeyFile``::

import gi
gi.require_version('GLib', '2.0')
from gi.repository import GLib
kf = GLib.KeyFile()
kf.set_string('section1', 'key', 'value')
kf.set_string('section2', 'key', 'value')
kf.save_to_file('glib.ini')

The output file 'glib.ini' will be:: (I added line number)

  1 [section1]
  2 key=value
  3 
  4 [section2]
  5 key=value

without a superfluous final blank line.

--
components: Library (Lib)
files: final_blank_line.patch
keywords: patch
messages: 312608
nosy: tttnns
priority: normal
severity: normal
status: open
title: ConfigParser writes a superfluous final blank line
type: behavior
Added file: https://bugs.python.org/file47460/final_blank_line.patch

___
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32917>
___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com