surveydata (version 0.1-11)

as.surveydata: Coercion from and to surveydata.

Description

Methods for creating "surveydata" objects, testing for class, and coercion from other objects.

Usage

as.surveydata(x, sep = "_", exclude = "other",
    ptn = pattern(x),
    defaultPtn = list(sep = sep, exclude = exclude),
    renameVarlabels = FALSE)

Arguments

x

Object to coerce to surveydata

sep

Separator between question and subquestion names

exclude

Excludes from pattern search

ptn

A list with two elements, sep and exclude. See pattern and which.q for more detail. By default

defaultPtn

The default for ptn, if it doesn't exist in the object that is being coerced.

renameVarlabels

If TRUE, turns variable.labels attribute into a named vector, using names(x) as names.

See Also

surveydata-package, is.surveydata

Examples

# Create surveydata object

sdat <- data.frame(
    id   = 1:4,
    Q1   = c("Yes", "No", "Yes", "Yes"),
    Q4_1 = c(1, 2, 1, 2), 
    Q4_2 = c(3, 4, 4, 3), 
    Q4_3 = c(5, 5, 6, 6), 
    Q10 = factor(c("Male", "Female", "Female", "Male")),
    crossbreak  = c("A", "A", "B", "B"), 
    weight      = c(0.9, 1.1, 0.8, 1.2)
)

varlabels(sdat) <- c(
    "RespID",
    "Question 1", 
    "Question 4: red", "Question 4: green", "Question 4: blue", 
    "Question 10",
    "crossbreak",
    "weight"
  )

sv <- as.surveydata(sdat, renameVarlabels=TRUE)

# Extract specific questions
sv[, "Q1"]
sv[, "Q4"]

# Query attributes
varlabels(sv)
pattern(sv)

# Find unique questions

questions(sv)
which.q(sv, "Q1")
which.q(sv, "Q4")

# Find question text
qText(sv, "Q1")
qText(sv, "Q4")

qTextCommon(sv, "Q4")
qTextUnique(sv, "Q4")


# Basic operations on a surveydata object, illustrated with the example dataset membersurvey

class(membersurvey)

questions(membersurvey)

which.q(membersurvey, "Q1")
which.q(membersurvey, "Q3")
which.q(membersurvey, c("Q1", "Q3"))

qText(membersurvey, "Q3")
qTextUnique(membersurvey, "Q3")
qTextCommon(membersurvey, "Q3")

# Extracting columns from a surveydata object

head(membersurvey[, "Q1"])
head(membersurvey["Q1"])
head(membersurvey[, "Q3"])
head(membersurvey[, c("Q1", "Q3")])

# Note that the result is always a surveydata object, even if only one column is extracted

head(membersurvey[, "id"])
str(membersurvey[, "id"])