Computes the absolute values of a variable

Computes the absolute values for a specified numeric or integer vector. This function is similar to R function abs.

ds.abs(x = NULL, newobj = NULL, datasources = NULL)

Arguments

x

a character string providing the name of a numeric or an integer vector.

newobj

a character string that provides the name for the output variable that is stored on the data servers. Default name is set to abs.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.abs assigns a vector for each study that includes the absolute values of the input numeric or integer vector specified in the argument x. The created vectors are stored in the servers.

Details

The function calls the server-side function absDS that computes the absolute values of the elements of a numeric or integer vector and assigns a new vector with those absolute values on the server-side. The name of the new generated vector is specified by the user through the argument newobj, otherwise is named by default to abs.newobj.

Author

Demetris Avraam for DataSHIELD Development Team

Examples

if (FALSE) { # \dontrun{

  # 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") 
  
  # Example 1: Generate a normally distributed variable with zero mean and variance equal
  #  to one and then get their absolute values
  ds.rNorm(samp.size=100, mean=0, sd=1, newobj='var.norm', datasources=connections)
  # check the quantiles
  ds.summary(x='var.norm', datasources=connections)
  ds.abs(x='var.norm', newobj='var.norm.abs', datasources=connections)
  # check now the changes in the quantiles
  ds.summary(x='var.norm.abs', datasources=connections)  

  # Example 2: Generate a sequence of negative integer numbers from -200 to -100
  # and then get their absolute values
  ds.seq(FROM.value.char = '-200', TO.value.char = '-100', BY.value.char = '1', 
         newobj='negative.integers', datasources=connections)
  # check the quantiles
  ds.summary(x='negative.integers', datasources=connections)
  ds.abs(x='negative.integers', newobj='positive.integers', datasources=connections)
  # check now the changes in the quantiles
  ds.summary(x='positive.integers', datasources=connections)

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

} # }