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.itemmethods, any atomic vector; for theunique,summary,str,print,[, and<-methods, a vector with classlabelled. 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 asx(which defines individual missing values) and"range"a matrix with two rows with the same mode asx(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 ofxthat are to be considered as valid, or an object of class"valid.values". valid.range-
either a vector of the same mode as
xand length 2, defining a range of valid values ofx, 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)
Nmnl. item w/ 5 labels for 1,2,3,... + ms.v. int [1:20] 1 2 3 4 5 1 2 3 4 5
...
summary(x)
First Second Third Fourth *Don't know
4 4 4 4 4
as.numeric(x)
[1] 1 2 3 4 NA 1 2 3 4 NA 1 2 3 4 NA 1 2 3 4 NA
attr(,"label")
[1] "test"
test <- as.item(rep(1:6,2),labels=structure(1:6,
names=letters[1:6]))
test
Item (measurement: nominal, type: integer, length = 12)
[1:12] a b c d e f a b c d e f
test == 1
[1] TRUE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
test != 1
[1] FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
test == "a"
[1] TRUE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
test != "a"
[1] FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
test == c("a","z")
[1] TRUE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
test != c("a","z")
[1] FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
test
Item (measurement: nominal, type: integer, length = 12)
[1:12] a b c d e f a b c d e f
test
Item (measurement: nominal, type: integer, length = 12)
[1:12] a b c d e f a b c d e f
codebook(test)
====================================================================================================
test
----------------------------------------------------------------------------------------------------
Storage mode: integer
Measurement: nominal
Values and labels N Percent
1 'a' 2 16.7
2 'b' 2 16.7
3 'c' 2 16.7
4 'd' 2 16.7
5 'e' 2 16.7
6 'f' 2 16.7
Test <- as.item(rep(letters[1:6],2),
labels=structure(letters[1:6],
names=LETTERS[1:6]))
Test
Item (measurement: nominal, type: character, length = 12)
[1:12] A B C D E F A B C D E F
Test == "a"
[1] TRUE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
Test != "a"
[1] FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
Test == "A"
[1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
Test != "A"
[1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
Test == c("a","z")
[1] TRUE FALSE FALSE FALSE FALSE FALSE TRUE FALSE FALSE FALSE FALSE FALSE
Test != c("a","z")
[1] FALSE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE
Test
Item (measurement: nominal, type: character, length = 12)
[1:12] A B C D E F A B C D E F
Test
Item (measurement: nominal, type: character, length = 12)
[1:12] A B C D E F A B C D E F
as.factor(test)
[1] a b c d e f a b c d e f
Levels: a b c d e f
as.factor(Test)
[1] A B C D E F A B C D E F
Levels: A B C D E F
as.numeric(test)
[1] 1 2 3 4 5 6 1 2 3 4 5 6
as.character(test)
[1] "a" "b" "c" "d" "e" "f" "a" "b" "c" "d" "e" "f"
as.character(Test)
[1] "A" "B" "C" "D" "E" "F" "A" "B" "C" "D" "E" "F"
as.data.frame(test)[[1]]
[1] a b c d e f a b c d e f
Levels: a b c d e f
