memisc: items – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

items

Survey Items

Description

Objects of class item are data vectors with additional information attached to them like “value labels” and “user-defined missing values” known from software packages like SPSS or Stata.

The class item is intended to facilitate data management of survey data. Objects in this class should not directly used in data analysis. Instead they should changed into "ordinary" vectors or factors before. For this see the documentation for as.vector,item-method.

Usage

## The constructor for objects of class "item"
## more convenient than new("item",...)
## S4 method for signature 'numeric'
as.item(x,
  labels=NULL,  missing.values=NULL,
  valid.values=NULL,  valid.range=NULL,
  value.filter=NULL,  measurement=NULL,
  annotation=attr(x,"annotation"), ...
  )
## S4 method for signature 'character'
as.item(x,
  labels=NULL,  missing.values=NULL,
  valid.values=NULL,  valid.range=NULL,
  value.filter=NULL,  measurement=NULL,
  annotation=attr(x,"annotation"), ...
  )

## S4 method for signature 'logical'
as.item(x,...)
# x is first coerced to integer,
# arguments in ... are then passed to the "numeric"
# method.

## S4 method for signature 'factor'
as.item(x,...)
## S4 method for signature 'ordered'
as.item(x,...)
## S4 method for signature 'POSIXct'
as.item(x,...)

## S4 method for signature 'double.item'
as.item(x,
  labels=NULL,  missing.values=NULL,
  valid.values=NULL,  valid.range=NULL,
  value.filter=NULL,  measurement=NULL,
  annotation=attr(x,"annotation"), ...
  )

## S4 method for signature 'integer.item'
as.item(x,
  labels=NULL,  missing.values=NULL,
  valid.values=NULL,  valid.range=NULL,
  value.filter=NULL,  measurement=NULL,
  annotation=attr(x,"annotation"), ...
  )

## S4 method for signature 'character.item'
as.item(x,
  labels=NULL,  missing.values=NULL,
  valid.values=NULL,  valid.range=NULL,
  value.filter=NULL,  measurement=NULL,
  annotation=attr(x,"annotation"), ...
  )

## S4 method for signature 'datetime.item'
as.item(x,
  labels=NULL,  missing.values=NULL,
  valid.values=NULL,  valid.range=NULL,
  value.filter=NULL,  measurement=NULL,
  annotation=attr(x,"annotation"), ...
  )

Arguments

`x`	for `as.item` methods, any atomic vector; for the `unique`, `summary`, `str`, `print`, `[`, and `<-` methods, a vector with class `labelled`.
`labels`	a named vector of the same mode as `x`.
`missing.values`	either a vector of the same mode as `x`, or a list with components `"values"`, vector of the same mode as `x` (which defines individual missing values) and `"range"` a matrix with two rows with the same mode as `x` (which defines a range of missing values), or an object of class `"missing.values"`.
`valid.values`	either a vector of the same mode as `x`, defining those values of `x` that are to be considered as valid, or an object of class `"valid.values"`.
`valid.range`	either a vector of the same mode as `x` and length 2, defining a range of valid values of `x`, or an object of class `"valid.range"`.
`value.filter`	an object of class `"value.filter"`, that is, of classes `"missing.values"`, `"valid.values"`, or `"valid.range"`.
`measurement`	level of measurement; one of "nominal", "ordinal", "interval", or "ratio".
`annotation`	a named character vector, or an object of class `"annotation"`
`...`	further arguments, ignored.

Examples

x <- as.item(rep(1:5,4),
      labels=c(
          "First"      = 1,
          "Second"     = 2,
          "Third"      = 3,
          "Fourth"     = 4,
          "Don't know" = 5
        ),
      missing.values=5,
      annotation = c(
        description="test"
      ))
  str(x)
  summary(x)
  as.numeric(x)

  test <- as.item(rep(1:6,2),labels=structure(1:6,
                                      names=letters[1:6]))
  test
  test == 1
  test != 1
  test == "a"
  test != "a"
  test == c("a","z")
  test != c("a","z")
  test 
  test 

  codebook(test)

  Test <- as.item(rep(letters[1:6],2),
                    labels=structure(letters[1:6],
                                     names=LETTERS[1:6]))
  Test
  Test == "a"
  Test != "a"
  Test == "A"
  Test != "A"
  Test == c("a","z")
  Test != c("a","z")
  Test 
  Test 

  as.factor(test)
  as.factor(Test)
  as.numeric(test)
  as.character(test)
  as.character(Test)

  as.data.frame(test)[[1]]

memisc

Management of Survey Data and Presentation of Analysis Results

v0.99.27.3

GPL-2

Authors

Martin Elff (with contributions from Christopher N. Lawrence, Dave Atkins, Jason W. Morgan, Achim Zeileis)

Initial release

2020-11-18