Re: Extracting unique values in an array (integer) ?

Christian,

I agree. We'll put this on our list as a high priority, as
it should be fairly easy to implement.

--Mary

On Wed, 5 Mar 2008, [ISO-8859-1] Christian Pagé wrote:

> Thanks Mary!
>
> Effectively, since that function is of potential use in many other NCL
> codes, I think that a built-in NCL function would be the best.
>
> Christian
>
> 2008/3/5, Mary Haley <haley_at_ucar.edu>:
>>
>> Hi Christian,
>>
>> I didn't read your email closely enough, and you did explain what
>> you meant the first time. My apologies.
>>
>> I don't think we have a function to do what you're asking. The
>> one way I thought of is a bit kludgy:
>>
>> years = (/1991,1990,1991,1990,1990,1990,1991,1991/)
>> qsort(years)
>> ny = dimsizes(years)
>> nuy = num((years(1:)-years(0:ny-2)).ne.0) + 1
>> print("Number of unique years = " + nuy)
>>
>> This may be a function worth "officially" adding to NCL, via a built-in
>> function, rather than one written in NCL.
>>
>>
>> --Mary
>>
>> On Wed, 5 Mar 2008, [ISO-8859-1] Christian Pagé wrote:
>>
>>> Hi Mary,
>>>
>>> I think I didn't explain correctly what I want to achieve.
>>>
>>> Let a vector of time (udunits in hours since), with daily data.
>>> I convert it to year, month, day, etc arrays using ut_calendar.
>>> I would like to know how many years I have... but I cannot use the
>> dimension
>>> of years since I will have 365/366 values of each year for complete
>> years,
>>> and less than that for incomplete years.
>>>
>>> Example :
>>> I have these two vectors with the same dimensions, years and months as
>>> follows.
>>> years = 1990 1990 1990 1990 1991 1991 1991 1991
>>> month = 09 10 11 12 01 02 03 04
>>>
>>> I want to know how many unique years I have in the years vector, which
>> would
>>> be equal to 2 in that example.
>>> It would be the same functionality as the sort -u | wc -l command in
>>> unix.
>>>
>>> Many thanks
>>>
>>> Christian
>>>
>>> 2008/3/5, Mary Haley <haley_at_ucar.edu>:
>>>>
>>>> Hi Christian,
>>>>
>>>> I have a weird connection at the moment and can't get to our web
>>>> pages, but I believe what you want is a function Dennis wrote called
>>>> generate_unique_indices.
>>>>
>>>> See:
>>>>
>>>>
>>>>
>>>>
>> http://www.ncl.ucar.edu/Document/Functions/Contributed/generate_unique_indices.shtml
>>>>
>>>>
>>>> --Mary
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, 4 Mar 2008, [ISO-8859-1] Christian Pagé wrote:
>>>>
>>>>> Hi everyone,
>>>>>
>>>>> I searched without success...
>>>>> I was wondering if there already exists a function in NCL to extract
>>>> unique
>>>>> values in an integer array ?
>>>>>
>>>>> Many thanks,
>>>>>
>>>>> --
>>>>> Christian Pagé
>>>>>
>>>
>
>
>
>
> --
> Christian Pagé
> http://meteocentre.com/toulouse/ http://meteoalerte.com/france/
> Ingénieur d'étude en climat, CERFACS, Toulouse
>

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Received on Wed Mar 12 2008 - 12:34:59 MDT