ds.replaceNA: Replaces the missing values in a vector

In paularaissa/dsTutorialClient: DataSHIELD client side functions for my first package

Description

This function identifies missing values and replaces them by a value or values specified by the analyst.

Usage

ds.replaceNA(x = NULL, forNA = NULL, newobj = NULL, checks = FALSE,
  datasources = NULL)

Arguments

x	a character, the name of the vector to process.
forNA	a list which contains the replacement value(s), a vector one or more values for each study. The length of the list must be equal to the number of servers the analyst is connected to.
newobj	a character, the name of the new vector in which missing values have been replaced. If no name is specified the default name is the name of the original vector followed by the suffix '.noNA' e.g. 'LAB_HDL.noNA' if the name of the vector is 'LAB_HDL'.
checks	a boolean, if TRUE (default) checks that verify elements on the server side such checks lengthen the run-time so the default is FALSE and one can switch these checks on (set to TRUE) when faced with some error(s).
datasources	a list of opal object(s) obtained after login in to opal servers; these objects hold also the data assign to R, as dataframe, from opal datasources.

Details

This function is used when the analyst prefer or requires complete vectors. It is then possible the specify one value for each missing value by first returning the number of missing values using the function ds.numNA but in most cases it might be more sensible to replace all missing values by one specific value e.g. replace all missing values in a vector by the mean or median value. Once the missing values have been replaced a new vector is created. NOTE: If the vector is within a table structure such as a data frame the new vector is appended to table structure so that the table hold hold both the vector with and without missing values. The latter is, by default, given a different that indicates its 'completeness'.

Value

a new vector or table structure with the same class is stored on the server site.

Author(s)

Gaye, A.

Examples

{

  # load that contains the login details
  data(logindata)

  # login and assign all the stored variables.
  opals <- datashield.login(logins=logindata,assign=TRUE)

  # Replace missing values in variable 'LAB_HDL' by the mean value in each study
  # first let us get the mean value for 'LAB_HDL' in each study
  ds.mean(x='D$LAB_HDL', type='split')

  # replace missing values in the variable 'LAB_HDL' in dataf frame 'D' by 
  # the mean value and name the new variable 'HDL.noNA'. 
  ds.replaceNA(x='D$LAB_HDL', forNA=list(1.569416, 1.556648), newobj='HDL.noNA')

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

}

paularaissa/dsTutorialClient documentation built on May 29, 2019, 7:36 a.m.