compare {compare}

Compare Two Objects

Description

Compare two objects and, if they are not the same, attempt to transform them to see if they are the same after being transformed.

Usage

compare(model, comparison,
        equal = TRUE,
        coerce = allowAll,
        shorten = allowAll,
        ignoreOrder = allowAll,
        ignoreNameCase = allowAll,
        ignoreNames = allowAll,
        ignoreAttrs = allowAll,
        round = FALSE,
        ignoreCase = allowAll,
        trim = allowAll,
        dropLevels = allowAll,
        ignoreLevelOrder = allowAll,
        ignoreDimOrder = allowAll,
        ignoreColOrder = allowAll,
        ignoreComponentOrder = allowAll,
        colsOnly = !allowAll,
        allowAll = FALSE)

compareName(model, compName,
            ...,
            ignore.case = TRUE,
            compEnv = .GlobalEnv)

Arguments

model

The “correct” object.

comparison

The object to be compared with the model.

equal

Test for equality if test for identity fails.

coerce

If objects are not the same, allow coercion of comparsion to model class.

shorten

If the length of one object is less than the other, shorten the longer object.

ignoreOrder

Ignore the order of values when comparing.

ignoreNameCase

Ignore the case of names when comparing.

ignoreNames

Ignore names attributes altogether.

ignoreAttrs

Ignore attributes altogether.

round

If objects are not the same, allow numbers to be rounded.

ignoreCase

Ignore the case of string values.

trim

Ignore leading and trailing spaces in string values.

dropLevels

If factors are not the same, allow unused levels to be dropped.

ignoreLevelOrder

Ignore the order of factor levels.

ignoreDimOrder

Ignore the order of dimensions when comparing matrices, arrays, or tables.

ignoreColOrder

Ignore the order of columns when comparing data frames.

ignoreComponentOrder

Ignore the order of components when comparing lists.

colsOnly

Only transform columns (not rows) when comparing data frames.

allowAll

Allow any sort of transformation (almost; see Details).

compName

A string giving the name of the comparison object.

...

Arguments to be passed to compare().

ignore.case

Ignore the case of the name when searching for the comparison object.

compEnv

An environment within which to search for the comparison object.

Details

The compare() function compares two objects for equality. The arguments allow for various transformations of the objects (e.g., type coercion) in order to try and achieve equality.

Specific transformations can be turned on via the appropriate argument, or the allowAll argument can be used to enable all transformations, with the exception of rounding of numeric values.

The compareName() function is a wrapper for compare() that requires the name of the comparison object rather than the objects itself, plus it allows an environment to be supplied that contains the actual comparison object. This is useful for the situation where a particular object with a particular name should have been generated and allows the generated object to differ from the desired object in terms of the case of its name.

Value

An object of class "comparison".

This is a list. The most important components are result, which gives the overall success/failure of the comparison, and transform, which describes the transformations attempted during the comparison (whether they were successful or not).

Author(s)

Paul Murrell

See Also

comparison-class and compareEqual

Examples

obj1 <- c("a", "a", "b", "c")
obj2 <- factor(obj1)
compare(obj1, obj2, allowAll=TRUE)