Creates missing values columns in the server-side

Adds extra columns with missing values in a data frame on the server-side.

ds.dataFrameFill(df.name = NULL, newobj = NULL, datasources = NULL)

Arguments

df.name

a character string representing the name of the input data frame that will be filled with extra columns of missing values.

newobj

a character string that provides the name for the output data frame that is stored on the data servers. Default value is "dataframefill.newobj".

datasources

a list of DSConnection-class objects obtained after login. If the datasources argument is not specified the default set of connections will be used: see datashield.connections_default.

Value

ds.dataFrameFill returns the object specified by the newobj argument which is written to the server-side. Also, two validity messages are returned to the client-side indicating the name of the newobj that has been created in each data source and if it is in a valid form.

Details

This function checks if the input data frames have the same variables (i.e. the same column names) in all of the used studies. When a study does not have some of the variables, the function generates those variables as vectors of missing values and combines them as columns to the input data frame. If any of the generated variables are of class factor, the function assigns to those the corresponding levels of the factors given from the studies where such factors exist.

Server function called: dataFrameFillDS

Author

Demetris Avraam for DataSHIELD Development Team

Examples

if (FALSE) { # \dontrun{

  ## Version 6, for version 5 see the Wiki 
  # Connecting to the Opal servers

  require('DSI')
  require('DSOpal')
  require('dsBaseClient')

  builder <- DSI::newDSLoginBuilder()
  builder$append(server = "study1", 
                 url = "http://192.168.56.100:8080/", 
                 user = "administrator", password = "datashield_test&", 
                 table = "CNSIM.CNSIM1", driver = "OpalDriver")
  builder$append(server = "study2", 
                 url = "http://192.168.56.100:8080/", 
                 user = "administrator", password = "datashield_test&", 
                 table = "CNSIM.CNSIM2", driver = "OpalDriver")
  builder$append(server = "study3",
                 url = "http://192.168.56.100:8080/", 
                 user = "administrator", password = "datashield_test&", 
                 table = "CNSIM.CNSIM3", driver = "OpalDriver")
                 
  logindata <- builder$build()
  
  # Log onto the remote Opal training servers
  connections <- DSI::datashield.login(logins = logindata, assign = TRUE, symbol = "D") 
  
  # Create two data frames with one different column
  
  ds.dataFrame(x = c("D$LAB_TSC","D$LAB_TRIG","D$LAB_HDL",
                     "D$LAB_GLUC_ADJUSTED","D$PM_BMI_CONTINUOUS"),
               newobj = "df1",
               datasources = connections[1])
               
  ds.dataFrame(x = c("D$LAB_TSC","D$LAB_TRIG","D$LAB_HDL","D$LAB_GLUC_ADJUSTED"),
               newobj = "df1",
               datasources = connections[2])
  
  # Fill the data frame with NA columns
  
  ds.dataFrameFill(df.name = "df1",
                   newobj = "D.Fill",
                   datasources = connections[c(1,2)]) # Two servers are used


  # Clear the Datashield R sessions and logout
  datashield.logout(connections) 
} # }