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From Wail Alkowaileet <wael....@gmail.com>
Subject Re: Aggregate function on collection of ordered list
Date Tue, 08 Dec 2015 08:34:47 GMT
That's one thing I observed in the built-in functions. Some work perfectly
fine with the open type and some are not.
As for instance, if I want to do string-length on a string that's not
declared in my schema. I have to trick the compiler as such
string-length(string-concat(["",$mystring]) to infer the type of $mystring
as UNION(NULL, STRING) instead of ANY to satisfies the check conditions.

I really don't know what would be the best solution. However, I think it
would be better for open type queries to fail at runtime instead of compile
time. But ... from a user experience point-of-view, runtime fail can be
problematic in a situation where I can apply the function to the first n-1
of the records and fails at the last record.

On Tue, Dec 8, 2015 at 1:04 AM, Ildar Absalyamov <ildar.absalyamov@gmail.com
> wrote:

> That’s true, the trick will work only for homogeneous lists.
>
> On Dec 7, 2015, at 13:00, Ian Maxon <imaxon@uci.edu> wrote:
>
> We still can't declare a list of mixed type though, I don't think. I
> was trying that earlier and ran into some cryptic errors about Java
> typecasting. Hopefully that isn't necessary though as the NetCDF (or
> the json representation thereof) isn't dynamically structured (e.g.
> open types aren't necessary)?
>
> On Mon, Dec 7, 2015 at 12:48 PM, Ildar Absalyamov
> <ildar.absalyamov@gmail.com> wrote:
>
> Namrata,
>
> I assume the aforementioned query with record defined in let clause was
> only the example.
> That query indeed has a bug, but is happen only because the type of the
> list is not statically enforced.
>
> Do you load your data into dataset? I so what is the type of that dataset?
> If you enforce the type of your nested ordered lists upon data ingestion
> you can calculate the average:
>
> drop dataverse test if exists
> create dataverse test
> use dataverse test
>
> create type testType as {
> id: int32,
> list: [[double]]
> }
>
> create dataset testDS(testType) primary key id;
> insert into dataset testDS({"id": 1, "list": [[1.2, 2.3, 3.4],[6,3,7,2]]});
>
> for $x in dataset  testDS
> for $y in $x.list
> return {"avg": avg($y)}
>
> On Dec 7, 2015, at 09:57, Malarout, Namrata (398M-Affiliate) <
> Namrata.Malarout@jpl.nasa.gov> wrote:
>
> Hi,
>
> Wail, thanks for looking into it and explaining the use of for. I will be
> following the issue. However, working with my sample data  may be a little
> more tricky. I have a couple hundred of records which contain such nested
> ordered lists. I would like to perform an aggregation over all the values
> across all the records. Any suggestions on how to do it?
>
> Mike, thanks for understanding :) Appreciate all the help.
> -Namrata
>
> From: Michael Carey <mjcarey@ics.uci.edu <mailto:mjcarey@ics.uci.edu
> <mjcarey@ics.uci.edu>>>
> Reply-To: "users@asterixdb.incubator.apache.org <
> mailto:users@asterixdb.incubator.apache.org
> <users@asterixdb.incubator.apache.org>>" <
> users@asterixdb.incubator.apache.org <
> mailto:users@asterixdb.incubator.apache.org
> <users@asterixdb.incubator.apache.org>>>
> Date: Monday, December 7, 2015 at 7:28 AM
> To: "users@asterixdb.incubator.apache.org <
> mailto:users@asterixdb.incubator.apache.org
> <users@asterixdb.incubator.apache.org>>" <
> users@asterixdb.incubator.apache.org <
> mailto:users@asterixdb.incubator.apache.org
> <users@asterixdb.incubator.apache.org>>>, "
> dev@asterixdb.incubator.apache.org <
> mailto:dev@asterixdb.incubator.apache.org
> <dev@asterixdb.incubator.apache.org>>" <dev@asterixdb.incubator.apache.org
> <mailto:dev@asterixdb.incubator.apache.org
> <dev@asterixdb.incubator.apache.org>>>
> Subject: Re: Aggregate function on collection of ordered list
>
> + Looping in the dev list to try and get fast attention to the fix, if
> it's easy!
> (I know that Namarata's under time pressure in a NASA bakeoff exercise.
> :-))
>
> On 12/7/15 4:59 AM, Wail Alkowaileet wrote:
>
> It's an easy fix...
> Thanks for reporting that.
>
> I reported it in https://issues.apache.org/jira/browse/ASTERIXDB-1216 <
> https://issues.apache.org/jira/browse/ASTERIXDB-1216>
>
> On Mon, Dec 7, 2015 at 3:33 PM, Wail Alkowaileet <wael.y.k@gmail.com <
> mailto:wael.y.k@gmail.com <wael.y.k@gmail.com>>> wrote:
> Hi Namrata,
>
> The best way to think of for in lists is to think it works as foreach in
> java.
> So ..
> in your first query, it should be like:
>
> let $l := [[1.2, 2.3, 3.4],[6,3,7,2]]
> for $x in $l // for each list in the outer list
> return {"avg”: avg($y)}
>
> However, I tried it and it seems that there is a bug for applying
> aggregation on nested open field.
>
> I'll look into it to see if it's an easy fix
>
>
>
> On Mon, Dec 7, 2015 at 2:52 PM, Malarout, Namrata (398M-Affiliate) <
> Namrata.Malarout@jpl.nasa.gov<mailto:Namrata.Malarout@jpl.nasa.gov
> <Namrata.Malarout@jpl.nasa.gov>>> wrote:
> Hi,
>
> I am trying to perform avg, sum, min and max functions on a collection of
> ordered lists. An example is:
> let $l := [[1.2, 2.3, 3.4],[6,3,7,2]]
> return {"avg”: avg($l)}
>
> I have tried both avg and sql-avg. But I get the following error:
> Cannot compute AVG for values of type ORDEREDLIST
> [NotImplementedException].
>
> I’ve attached the sample data that I’m working with (sample.adm). My AQL
> query to find the average of analysis_error looks like:
>
> use dataverse Test;
> for $f in dataset sample
> where not(is-null($f.analysis_error))
> return avg($f.analysis_error);
>
> The error seen is as follows:
> Type of argument in function-call: asterix:avg, Args:[function-call:
> asterix:field-access-by-name, Args:[%0->$$0, AString: {analysis_error}]]
> should be a collection type instead of ANY [AlgebricksException]
>
> I would like to know what is the correct syntax to find the average.
> Appreciate the help.
> Thanks,
> Namrata
>
>
>
>
>
> --
>
> Regards,
> Wail Alkowaileet
>
>
>
> --
>
> Regards,
> Wail Alkowaileet
>
>
>
> Best regards,
> Ildar
>
>
> Best regards,
> Ildar
>
>


-- 

*Regards,*
Wail Alkowaileet

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