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spilt question

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  spilt question loial <jldunn2000@gmail.com> - 2013-05-16 08:00 -0700
    Re: spilt question Walter Hurry <walterhurry@lavabit.com> - 2013-05-16 15:10 +0000
    Re: spilt question Fábio Santos <fabiosantosart@gmail.com> - 2013-05-16 16:14 +0100
    Re: spilt question Chris Angelico <rosuav@gmail.com> - 2013-05-17 01:15 +1000
    Re: spilt question Dave Angel <davea@davea.name> - 2013-05-16 11:20 -0400
    Re: spilt question Tim Chase <python.list@tim.thechases.com> - 2013-05-16 10:23 -0500
    Re: spilt question Ned Batchelder <ned@nedbatchelder.com> - 2013-05-16 11:22 -0400
    Re: spilt question Dave Angel <davea@davea.name> - 2013-05-16 11:32 -0400

#45428 — spilt question

I want to split a string so that I always return everything BEFORE the LAST underscore

HELLO_xxxxxxxx.lst         # should return HELLO
HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE

I have tried with rsplit but cannot get it to work.

Any help appreciated

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#45430

On Thu, 16 May 2013 08:00:25 -0700, loial wrote:

> I want to split a string so that I always return everything BEFORE the
> LAST underscore
> 
> HELLO_xxxxxxxx.lst         # should return HELLO
> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
> 
> I have tried with rsplit but cannot get it to work.
> 
mystr.rsplit("_",1)[0]

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#45431

[Multipart message — attachments visible in raw view] — view raw

str.split takes a limit argument. Try your_string.split('_', 1)
On 16 May 2013 16:11, "loial" <jldunn2000@gmail.com> wrote:

> I want to split a string so that I always return everything BEFORE the
> LAST underscore
>
> HELLO_xxxxxxxx.lst         # should return HELLO
> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
>
> I have tried with rsplit but cannot get it to work.
>
> Any help appreciated
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>

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#45432

On Fri, May 17, 2013 at 1:00 AM, loial <jldunn2000@gmail.com> wrote:
> I want to split a string so that I always return everything BEFORE the LAST underscore
>
> HELLO_xxxxxxxx.lst         # should return HELLO
> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
>
> I have tried with rsplit but cannot get it to work.
>
> Any help appreciated

Try with a limit:

>>> "HELLO_GOODBYE_xxxxxxxx.ls".rsplit("_",1)
['HELLO_GOODBYE', 'xxxxxxxx.ls']
>>> "HELLO_GOODBYE_xxxxxxxx.ls".rsplit("_",1)[0]
'HELLO_GOODBYE'

You can easily get docs on it:

>>> help("".rsplit)
Help on built-in function rsplit:

rsplit(...)
    S.rsplit(sep=None, maxsplit=-1) -> list of strings

    Return a list of the words in S, using sep as the
    delimiter string, starting at the end of the string and
    working to the front.  If maxsplit is given, at most maxsplit
    splits are done. If sep is not specified, any whitespace string
    is a separator.

ChrisA

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#45434

On 05/16/2013 11:00 AM, loial wrote:
> I want to split a string so that I always return everything BEFORE the LAST underscore
>
> HELLO_xxxxxxxx.lst         # should return HELLO
> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
>
> I have tried with rsplit but cannot get it to work.
>
> Any help appreciated
>

The rsplit() method was a good idea; it will work.  So exactly what did 
you try and what about it did not work.  How are you stuck going from 
your partial answer to a complete one?

While you're at it, you need to consider at least two more cases

HELLO.txt                    #should return ""
HELLO_and_____goodbye        #should return "HELLO_and____"

-- 
DaveA

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#45435

On 2013-05-16 08:00, loial wrote:
> I want to split a string so that I always return everything BEFORE
> the LAST underscore
> 
> HELLO_xxxxxxxx.lst         # should return HELLO
> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
> 
> I have tried with rsplit but cannot get it to work.

 .rsplit takes an optional "how many splits do you want?" parameter
 that defaults to giving you all of them.  Just ask for one
 right-most split:

  TESTS = [
     ("HELLO_xxxxxxx.lst", "HELLO"),
     ("HELLO_GOODBYE_xxxxx.ls", "HELLO_GOODBYE"),
     ]

  for input, expected in TESTS:
    result = input.rsplit('_', 1)[0]
    if result == expected:
      verdict = "passed"
    else:
      verdict = "failed"
    print "%r -> %r == %r  (%s)" % (
      input,
      result,
      expected,
      verdict,
      )

-tkc

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#45436

[Multipart message — attachments visible in raw view] — view raw

On 5/16/2013 11:00 AM, loial wrote:
> I want to split a string so that I always return everything BEFORE the LAST underscore
>
> HELLO_xxxxxxxx.lst         # should return HELLO
> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
>
> I have tried with rsplit but cannot get it to work.
>
> Any help appreciated
>
     >>> "HELLO_GOODBYE_xxxxxxxx.ls".rpartition('_')
    ('HELLO_GOODBYE', '_', 'xxxxxxxx.ls')
     >>> "HELLO_GOODBYE_xxxxxxxx.ls".rsplit('_', 1)
    ['HELLO_GOODBYE', 'xxxxxxxx.ls']
     >>> "HELLO_GOODBYE_xxxxxxxx.ls".rpartition('_')[0]
    'HELLO_GOODBYE'
     >>> "HELLO_GOODBYE_xxxxxxxx.ls".rsplit('_', 1)[0]
    'HELLO_GOODBYE'


For the future, getting help works better if you show what you tried, 
and what it produced.

--Ned.

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#45437

On 05/16/2013 11:15 AM, Chris Angelico wrote:
> On Fri, May 17, 2013 at 1:00 AM, loial <jldunn2000@gmail.com> wrote:
>> I want to split a string so that I always return everything BEFORE the LAST underscore
>>
>> HELLO_xxxxxxxx.lst         # should return HELLO
>> HELLO_GOODBYE_xxxxxxxx.ls  # should return HELLO_GOODBYE
>>
>> I have tried with rsplit but cannot get it to work.
>>
>> Any help appreciated
>
> Try with a limit:
>
>>>> "HELLO_GOODBYE_xxxxxxxx.ls".rsplit("_",1)
> ['HELLO_GOODBYE', 'xxxxxxxx.ls']
>>>> "HELLO_GOODBYE_xxxxxxxx.ls".rsplit("_",1)[0]
> 'HELLO_GOODBYE'
>
> You can easily get docs on it:
>
>>>> help("".rsplit)
> Help on built-in function rsplit:
>
> rsplit(...)
>      S.rsplit(sep=None, maxsplit=-1) -> list of strings
>
>      Return a list of the words in S, using sep as the
>      delimiter string, starting at the end of the string and
>      working to the front.  If maxsplit is given, at most maxsplit
>      splits are done. If sep is not specified, any whitespace string
>      is a separator.
>
> ChrisA
>

Now that you've all done his homework for him, see if The OP can spot 
the one case where that won't work.  It's easy to test for, but still 
important to get right (for some definition of right).

-- 
DaveA

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