如何在H2O中實現data.table中的.N，R？

請考慮以下代碼。如何在H2O中實現data.table中的.N，R？

library(data.table) 

data1x <- "x row1 
1 1 
1 2 
1 3 
1 4 
2 1 
2 2 
2 3 
3 1 
4 2" 

data1 <- read.table(textConnection(data1x), header=TRUE) 
setDT(data1) 
data1[, seqN := 1:.N, by="x"]

我想在h2o數據幀上做類似的事情。我仔細閱讀了用戶手冊，但無法弄清楚如何使用h20進行操作。

編輯：我嘗試下面的代碼，用於水，但它給錯誤：

library(h2o) 
h2o.init() 
data1x <- "x row1 
1 1 
1 2 
1 3 
1 4 
2 1 
2 2 
2 3 
3 1 
4 2" 
data1x <- read.table(textConnection(data1x), header=TRUE) 
data1xH2O <- as.h2o(data1x) 

fun = function(df) { 
    1:nrow(df) 
} 

h2o.ddply(data1xH2O, "x", fun)

這將導致以下錯誤：

ERROR: Unexpected HTTP Status code: 400 Bad Request (url = http://localhost:54321/99/Rapids) 

water.rapids.Rapids.IllegalASTException 
[1] "water.rapids.Rapids$IllegalASTException: Missing a number"             
[2] " water.rapids.Rapids.number(Rapids.java:312)"                
[3] " water.rapids.Rapids.parseNumList(Rapids.java:243)"              
[4] " water.rapids.Rapids.parseList(Rapids.java:208)"               
[5] " water.rapids.Rapids.parseNext(Rapids.java:140)"               
[6] " water.rapids.Rapids.parseFunctionDefinition(Rapids.java:193)"            
[7] " water.rapids.Rapids.parseNext(Rapids.java:139)"               
[8] " water.rapids.Rapids.parseFunctionApplication(Rapids.java:158)"           
[9] " water.rapids.Rapids.parseNext(Rapids.java:138)"               
[10] " water.rapids.Rapids.parseFunctionApplication(Rapids.java:158)"           
[11] " water.rapids.Rapids.parseNext(Rapids.java:138)"               
[12] " water.rapids.Rapids.parse(Rapids.java:48)"                
[13] " water.rapids.Rapids.exec(Rapids.java:81)"                 
[14] " water.api.RapidsHandler.exec(RapidsHandler.java:39)"              
[15] " sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)"            
[16] " sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)"       
[17] " sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)"     
[18] " java.lang.reflect.Method.invoke(Method.java:483)"               
[19] " water.api.Handler.handle(Handler.java:61)"                
[20] " water.api.RequestServer.serve(RequestServer.java:412)"             
[21] " water.api.RequestServer.doGeneric(RequestServer.java:263)"            
[22] " water.api.RequestServer.doPost(RequestServer.java:200)"             
[23] " javax.servlet.http.HttpServlet.service(HttpServlet.java:755)"            
[24] " javax.servlet.http.HttpServlet.service(HttpServlet.java:848)"            
[25] " org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)"         
[26] " org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:503)"        
[27] " org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)"       
[28] " org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)"        
[29] " org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)"      
[30] " org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)"      
[31] " org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:429)"        
[32] " org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)"       
[33] " org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)"      
[34] " org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)"       
[35] " org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)"     
[36] " org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)"       
[37] " org.eclipse.jetty.server.Server.handle(Server.java:370)"             
[38] " org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)"   
[39] " org.eclipse.jetty.server.BlockingHttpConnection.handleRequest(BlockingHttpConnection.java:53)"   
[40] " org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:982)"     
[41] " org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1043)" 
[42] " org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:865)"           
[43] " org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:240)"         
[44] " org.eclipse.jetty.server.BlockingHttpConnection.handle(BlockingHttpConnection.java:72)"     
[45] " org.eclipse.jetty.server.bio.SocketConnector$ConnectorEndPoint.run(SocketConnector.java:264)"    
[46] " org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)"       
[47] " org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)"       
[48] " java.lang.Thread.run(Thread.java:745)"                 

Error in .h2o.doSafeREST(h2oRestApiVersion = h2oRestApiVersion, urlSuffix = page, : 


ERROR MESSAGE: 

Missing a number

任何建議，我能做些什麼刪除此錯誤。

來源

2017-01-23 Kumar Manglam

**如果不可能**，則可以**使用'as.data.frame'命令將h2o數據幀轉換爲R數據幀**。通過使用h2o將h2o數據幀轉換爲R數據幀，您可以運行以上代碼。 –

不，我需要將我的data.table邏輯轉移到H2O。 –

意思是你想用h2o在上面的代碼中實現一些邏輯。對？？ –