extract: Extract or replace subsets of surveydata, ensuring that the...

In andrie/surveydata: Tools to Work with Survey Data

Extract or replace subsets of surveydata, ensuring that the varlabels stay synchronized.

Description

The surveydata package makes it easy to extract specific questions from a surveydata object. Because survey data typically has question names like "Q1_a", "Q1_b", "Q1_c" the extract method for a surveydata object makes it easy to extract all columns by simply specifying "Q1" as the argument to the column index.

Usage

## S3 method for class 'surveydata'
x[i, j, drop = FALSE]

## S3 replacement method for class 'surveydata'
x[i, j] <- value

## S3 replacement method for class 'surveydata'
x$name <- value

Arguments

x	surveydata object
i	row index
j	column index
drop	logical. Passed to [.data.frame. Note that the default is FALSE.
value	New value
name	Names of columns

Details

Extraction is similar to data frames, with three important exceptions:

• The column argument j is evaluated using which.q() and will return all columns where the column names match the pattern().

• The drop argument is FALSE. Thus the result will always be a surveydata object, even if only a single column is returned.

• All extraction methods retain the pattern and varlabels arguments.

See Also

surveydata-package, varlabels

Examples

names(membersurvey)
head(membersurvey["Q1"])
head(membersurvey[c("Q1", "Q2")])
head(membersurvey[membersurvey$Q2=="2009", c("Q1", "Q2")])

# The pattern is used to extract columns

pattern(membersurvey)

grep("Q20", names(membersurvey), value=TRUE)
head(membersurvey["Q20"])
head(membersurvey["Q20_other"])

andrie/surveydata documentation built on March 13, 2023, 2 a.m.