r - Returning copy of data.table from ReferenceClass method -


i try return copies of data.tables methods of referenceclass:

dummy <- setrefclass(   "dummy",   fields = list(     dt = "data.table"   ),   methods = list(     initialize = function( df ){       if( !missing( df ) ){         dt <<- data.table( df , key = "a" )       }     },     gettab = function( ix ){       return( copy(dt[ ix, ]) )     }   ) )

however, calling dummy$gettab() yields error don't understand:

d <- dummy$new( data.frame( = 1:10, b = 1:10 ) ) d$gettab( 2:5 )  error in if (shallow) assign(field, get(field, envir = selfenv), envir = venv) else { :    argument not interpretable logical in addition: warning message: in if (shallow) assign(field, get(field, envir = selfenv), envir = venv) else { :  condition has length > 1 , first element used

i have no clue, means , comes from. plus, following 2 procedures work without problems:

copy( d$dt[ 2:5 ] )  mycopy <- function( dt, ix ) {   return( copy(dt[ ix, ]) ) } mycopy( d$dt, 2:5 )

any appreciated.

ok sorry, dumb error, had overseen method envrefclass$copy(). solution call data.table::copy explicitly:

dummy <- setrefclass(   "dummy",   fields = list(     dt = "data.table"   ),   methods = list(     initialize = function( df ){       if( !missing( df ) ){         dt <<- data.table( df , key = "a" )       }     },     gettab = function( ix ){       return( data.table::copy(dt[ ix, ]) )     }   ) )

Comments

Post a Comment

Popular posts from this blog

Change php variable from jquery value using ajax (same page) -

what i'm trying this: i've php global variable $currentid , simple jquery script check if there "id" (page) in hash of url , if yes wanted give value $currentid . i've been reading lot , notice shall use ajax i'm not managing it. my code is: <script type="text/javascript"> $(document).ready(function(){ if (parent.location.hash != '' ) { var thecurrentid = parent.location.hash.split('#')[1]; $.ajax({ url: 'my.php', //current page type: 'post', data: {theid: thecurrentid }, datatype: 'json', success: function () { } }); } // code here }); </script> could me please? thank in advance. php server side language, meaning once has sent data browser, php variables , data cannot changed... however, using ajax, can send request php page , change data in dom based on result. consider th...
Read more

Pull out data related to my apps from Android Play Store and iOS App Store -

i want pull out data related apps (ratings, reviews, etc) google play store , apple app store ? how can accomplish ? i have found open source apis google mentioned not reliable. also there paid apis (e.g. appfigures) available. has idea how able pull data these play stores ?? i looking direction on how can accomplish this. can suggest ? we (appfigures) have been working on developing infrastructure give ability reviews , bunch of other data points major app stores several years :] we make available via our api though may want check out.
Read more

How can I fetch data from a web server in an android application? -

i want retrieve data web server in android application, , don't know begin. should use web services? i recommend these tutorials: connect android php , mysql , json in android , php , mysqli i used these tutorials , managed trying working without difficulty. between them describe each step in how attempting @ each stage, android application, database , web server side , has information included can process , use received information the thing add connect android php , mysql tutorial makes use of mysql_ in php deprecated. better use mysqli why included third link. the basic outline of want this: 1) in android app make request server php script using class this: import java.io.bufferedreader; import java.io.ioexception; import java.io.inputstream; import java.io.inputstreamreader; import java.io.unsupportedencodingexception; import java.util.list; import org.apache.http.httpentity; import org.apache.http.httpresponse; import org.apache.http.namevaluepair...
Read more