[Python-ideas] pathlib suggestions

[Stephan Houben]

Hi all,

It seems to me that the correct algorithm to get the "full suffix" is not
to take everything after the FIRST dot,
but rather to:
1. Recognize that the last suffix is one of the UNIX-style compression
tools .Z, .gz, ,bz2, .xz, .lzma (at least)
2. Then add the next-to-last suffix.

So we can then determine that the suffix of
  order.for.tar.ps.gz
is .ps.gz and the basename is order.for.tar .

However, I am not sure if we want to hard-code a list of such suffixes in
the standard library.
(Even though it could be user-extensible.)

Stephan

2017-01-25 16:33 GMT+01:00 Todd <toddrjen at gmail.com>:

> On Wed, Jan 25, 2017 at 10:18 AM, Petr Viktorin <encukou at gmail.com> wrote:
>
>> On 01/25/2017 04:04 PM, Todd wrote:
>>
>>> On Wed, Jan 25, 2017 at 12:25 AM, Stephen J. Turnbull
>>> <turnbull.stephen.fw at u.tsukuba.ac.jp
>>> <mailto:turnbull.stephen.fw at u.tsukuba.ac.jp>> wrote:
>>>
>>>     I'm just going to let fly with the +1s and -1s, don't take them too
>>>     seriously, they're basically impressionistic (I'm not a huge user of
>>>     pathlib yet).
>>>
>>>     Todd writes:
>>>
>>>      > So although the names are tentative, perhaps there could be a
>>>     "fullsuffix"
>>>      > property to return the extensions as a single string,
>>>
>>>     -0      '.'.join(p.suffixes) vs. p.fullsuffix?  TOOWTDI says no.  I
>>>             also don't really see the use case.
>>>
>>>
>>> The whole point of pathlib is to provide convenience functions for
>>> common path-related operations.  It is full of methods and properties
>>> that could be implemented other ways.
>>>
>>> Dealing with multi-part extensions, at least for me, is extremely
>>> common.  A ".tar.gz" file is not the same as a ".tar.bz2" or a
>>> ".svg.gz".  When I want to find a ".tar.gz" file, having to deal with
>>> the ".tar" and ".gz" parts separately is nothing but a nuisance.  If I
>>> want to find and extract ".rar" files, I don't want ".part1.rar" files,
>>> ".part2.rar" files, and so on.  So for me dealing with the extension as
>>> a single unit, rather than individual parts, is the most common
>>> approach.
>>>
>>
>> But what if the .tar.gz file is called "spam-4.2.5-final.tar.gz"?
>> Existing tools like glob and endswith() can deal with the ".tar.gz"
>> extension reliably, but "fullsuffix" would, arguably, not give the answers
>> you want.
>>
>
>
> I wouldn't use it in that situation.  The existing "suffix" and "stem"
> properties also only work reliably under certain situations.
>
>
>>
>> Perhaps more specialized tools would be useful, though, for example:
>>     repacked_path = original_path.replace_suffix(".tar.gz", ".zip")
>>
>>
> That is helpful if I want to rename, not if I want to (for example)
> uncompress a file.
>
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