core data - NSExpression is always returning zero -

-

i have entity called rounds has basic data golf rounds. trying calculate number of rounds average score. however, every time try , calculate these values returns 0 (zero). there no errors, , no crashes.

i have following function in rounds.m: 

+(nsnumber *)aggregateoperation:(nsstring *)function onattribute:(nsstring *)attributename withpredicate:(nspredicate *)predicate inmanagedobjectcontext:(nsmanagedobjectcontext *)context {     nsexpression *ex = [nsexpression expressionforfunction:function                                  arguments:[nsarray arraywithobject:[nsexpression expressionforkeypath:attributename]]];      nsexpressiondescription *ed = [[nsexpressiondescription alloc] init];     [ed setname:@"result"];     [ed setexpression:ex];     [ed setexpressionresulttype:nsinteger64attributetype];      nsarray *properties = [nsarray arraywithobject:ed];      nsfetchrequest *request = [[nsfetchrequest alloc] init];     [request setpropertiestofetch:properties];     [request setresulttype:nsdictionaryresulttype];      if (predicate != nil)         [request setpredicate:predicate];      nsentitydescription *entity = [nsentitydescription entityforname:@"rounds"                               inmanagedobjectcontext:context];     [request setentity:entity];      nsarray *results = [context executefetchrequest:request error:nil];     nsdictionary *resultsdictionary = [results objectatindex:0];     nsnumber *resultvalue = [resultsdictionary objectforkey:@"result"];     return resultvalue; }

i call method view controller set values of labels number of rounds , scoring average:

-(nsnumber*) scoringaveragecalc {     nsnumber *scoreaverage = [rounds aggregateoperation:@"average:" onattribute:@"roundscore" withpredicate:nil inmanagedobjectcontext:_managedobjectcontext];     return scoreaverage; }  -(nsnumber*)countofrounds {     nsnumber *roundcount = [rounds aggregateoperation:@"count:" onattribute:@"rounddate" withpredicate:nil inmanagedobjectcontext:_managedobjectcontext];     return roundcount; }

can please tell me why not getting correct value?

i think nsexpression overkill simple sums. this: fetch rounds normal managed objects (nsmanagedobjectresulttype) , use kvc should have aggregators need.

nsnumber *sum = [rounds valueforkeypath:@"@sum.score"]; nsnumber *avg = [rounds valueforkeypath:@"@avg.score"];

simple, isn't it? check out here.


Comments

Post a Comment

Popular posts from this blog

java - Run a .jar on Heroku -

-
i trying run .jar file on heroku, , can't find instructions anywhere on how this. have read wants me compile uploading heroku. possible, , if is, how this? if helps, trying run minecraft craftbukkit server, , don't have pom.xml file yet. you didn't provide details i'll try give , people reaches question way it. first of all, create heroku account , create heroku application (assumed have done that). second, need generate application jar , upload heroku. so, open terminal , install heroku cli (assuming unix terminal): $ sudo npm install -g heroku-cli you need have npm , nodejs installed, can check link: https://www.digitalocean.com/community/tutorials/how-to-install-node-js-on-ubuntu-16-04 once done that, can use npm update node version acceptable heroku-cli: $ sudo npm install -g n $ sudo n 7.10.0 and run: $ sudo npm install -g heroku-cli in order deploy jars, need install deploy plugin: $ sudo heroku plugins:install heroku-cli-deploy ...
Read more

java - Jtable duplicate Rows -

-
Image
when add new rows in jtable duplicate rows many times this method update jtable public final void tableaucomande(){ ((defaulttablemodel)tabcommande.getmodel()).getdatavector().clear(); session s=hibernateutil.getsessionfactory().opensession(); criteria cr1= s.createcriteria(commande.class); list <commande> lcs=cr1.list() ; criteria cr2= s.createcriteria(lignecommande.class); list <lignecommande> lck=cr2.list() ; if(lcs.size()!=0 && lck.size()!=0) { (commande lc:lcs) { for(lignecommande lig:lck){ ((defaulttablemodel)tabcommande.getmodel()).addrow(new object[]{ lc.getid_cmd(),lc.getnumcmd(),lc.getdate_cmd(),lc.getclient().getnomprenom(), lig.getproduit().getlib_prd(),lig.getquantite(),lig.getproduit().getid_prd() }); } } // tabcommande.setrowselectioninterval(tabcommande.getrowcount()-1,tabcommande.getrowcount()-1); } } this code add add data rows displaye...
Read more

validation - How to pass paramaters like unix into windows batch file -

-
i need pass various parameters .cmd file unix format file.cmd -configuration=value -source=value -flag but, try this: startlocal @echo off cls setlocal set cmdline=%* set configuration= set source= set badargs= set validation= goto main :splitargs echo splitargs(%*) if "%*" neq "" ( /f "tokens=1,2,* delims== " %%i in ("%*") call :assignkeyvalue %%i %%j & call :splitargs %%k ) goto :eof :assignkeyvalue echo assignkeyvalue(%1, %2) if /i %1==-configuration ( set configuration=%2 ) else if /i %1==-source ( set source=%2 ) else ( rem append unrecognised [key,value] badargs echo unknown key %1 set badargs=%badargs%[%1, %2] ) goto :eof :validate echo validating set validation=fail if defined configuration ( echo -configuration ok if defined source ( echo -source ok if not defined badargs ( set validation=success ) ) ) goto :eof :main cl...
Read more