items: Survey Items

In memisc: Tools for Management of Survey Data and the Presentation of Analysis Results

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.

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 as.character, as.factor, as.integer, as.double, a vector with class "item"; 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.

See Also

annotation labels value.filter

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]]

Example output

Loading required package: lattice
Loading required package: MASS

Attaching package: 'memisc'

The following objects are masked from 'package:stats':

    contr.sum, contr.treatment, contrasts

The following object is masked from 'package:base':

    as.array

 Nmnl. item w/ 5 labels for 1,2,3,... + ms.v.  int [1:20] 1 2 3 4 5 1 2 3 4 5 ...
      First      Second       Third      Fourth *Don't know 
          4           4           4           4           4 
 [1]  1  2  3  4 NA  1  2  3  4 NA  1  2  3  4 NA  1  2  3  4 NA

Item (measurement: nominal, type: integer, length = 12) 

 [1:12] a b c d e f a b c d e f
 [1]  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
 [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE
 [1]  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
 [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE
 [1]  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
 [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE

Item (measurement: nominal, type: integer, length = 12) 

 [1:12] a b c d e f a b c d e f

Item (measurement: nominal, type: integer, length = 12) 

 [1:12] a b c d e f a b c d e f
================================================================================

   test

--------------------------------------------------------------------------------

   Storage mode: integer
   Measurement: nominal

   Values and labels    N    Percent 
                                     
             1   'a'    2   16.7 16.7
             2   'b'    2   16.7 16.7
             3   'c'    2   16.7 16.7
             4   'd'    2   16.7 16.7
             5   'e'    2   16.7 16.7
             6   'f'    2   16.7 16.7


Item (measurement: nominal, type: character, length = 12) 

 [1:12] A B C D E F A B C D E F
 [1]  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
 [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE
 [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [1]  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE
 [1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE

Item (measurement: nominal, type: character, length = 12) 

 [1:12] A B C D E F A B C D E F

Item (measurement: nominal, type: character, length = 12) 

 [1:12] A B C D E F A B C D E F
 [1] a b c d e f a b c d e f
Levels: a b c d e f
 [1] A B C D E F A B C D E F
Levels: A B C D E F
 [1] 1 2 3 4 5 6 1 2 3 4 5 6
 [1] "a" "b" "c" "d" "e" "f" "a" "b" "c" "d" "e" "f"
 [1] "A" "B" "C" "D" "E" "F" "A" "B" "C" "D" "E" "F"
 [1] a b c d e f a b c d e f
Levels: a b c d e f

memisc documentation built on May 2, 2019, 5:45 p.m.