ds.asNumeric {dsBaseClient}

R Documentation

Converts a server-side R object into a numeric class

Description

Coerces an R object into a numeric class. This function is based on the native R function as.numeric.

Usage

ds.asNumeric(x.name = NULL, newobj = NULL, datasources = NULL)

Arguments

x.name	a character string providing the name of the input object to be coerced to a numeric.
newobj	a character string that provides the name for the output object that is stored on the data servers. Default asnumeric.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.

Details

This function is based on the native R function as.numeric. However, it behaves differently with some specific classes of variables. For example, if the input object is of class factor, it first converts its values into characters and then convert those to numerics. This behavior is important for the case where the input object is of class factor having numbers as levels. In that case, the native R as.numeric function returns the underlying level codes and not the values as numbers. For example as.numeric in R converts the factor vector:
0 1 1 2 1 0 1 0 2 2 2 1
Levels: 0 1 2
to the following numeric vector: 1 2 2 3 2 1 2 1 3 3 3 2
In contrast DataSHIELD converts an input factor with numeric levels to its original numeric values.

Server function called: asNumericDS

Value

ds.asNumeric returns the R object converted into a numeric class that is written to the server-side. Also, two validity messages are returned to the client-side indicating the name of the newobj which has been created in each data source and if it is in a valid form.

Author(s)

DataSHIELD Development Team

Examples

## Not run: 
  ## 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()
  
  connections <- DSI::datashield.login(logins = logindata, assign = TRUE, symbol = "D") 
  
  # Converting the R object into a numeric class
  ds.asNumeric(x.name = "D$LAB_TSC",
                  newobj = "num.obj",
                  datasources = connections[1]) #only the first Opal server is used ("study1")
  ds.class(x = "num.obj", datasources = connections[1]) 
                
  # Clear the Datashield R sessions and logout                 
  datashield.logout(connections) 
  

## End(Not run)   

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