Aggregate identical cases.

Description

Function to aggregate identical cases.

Usage

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wcAggregateCases(x, weights = NULL, ...)
## S3 method for class 'data.frame'
wcAggregateCases(x, weights=NULL, ...) 
## S3 method for class 'matrix'
wcAggregateCases(x, weights=NULL, ...) 
## S3 method for class 'wcAggregateCases'
print(x,  ...) 

Arguments

x

The object to aggregate.

weights

Numeric. An optional case weights vector.

...

Optional additionnal arguments.

Value

A wcAggregateCases object with the following components:

aggIndex

Index of the unique cases in the original object data.

aggWeights

Aggregated case weights

disaggIndex

Index of the original object data in the unique cases.

disaggWeights

Original weights used.

Examples

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data(mvad)
## Taking only the father unemployment and 
## success at the end of compulsory schooling.
myData <- mvad[ , c("funemp", "gcse5eq")]
## Computing aggregated cases informations
ac <- wcAggregateCases(myData, weights=mvad$weight)
print(ac)
## Retrieving unique cases in the original data set
uniqueData <- myData[ac$aggIndex, ]
## Table from original data
table.orig <- xtabs(mvad$weight~funemp+gcse5eq, data=myData)

## Table from aggregated data
table.agg <- xtabs(ac$aggWeights~funemp+gcse5eq, data=uniqueData)

## Both table are equal, no information is lost 
## (only the call command is different)
all(table.orig == table.agg)