map_values-methods: Map Values from One Set to Another Using a User-supplied...

In bbuchsbaum/neuroim2: Data Structures for Brain Imaging Data

Map Values from One Set to Another Using a User-supplied Lookup Table

Description

This function maps values from one set to another using a lookup table provided by the user.

Usage

map_values(x, lookup)

## S4 method for signature 'NeuroVol,list'
map_values(x, lookup)

## S4 method for signature 'NeuroVol,matrix'
map_values(x, lookup)

Arguments

x	The object from which values will be mapped.
lookup	The lookup table. The first column is the "key" and the second column is the "value".

Value

An object of the same class as x, in which the original values have been replaced with the lookup table values.

Examples

x <- NeuroSpace(c(10, 10, 10), c(1, 1, 1))
vol <- NeuroVol(sample(1:10, 10 * 10 * 10, replace = TRUE), x)

## Lookup table is a list
lookup <- lapply(1:10, function(i) i * 10)
names(lookup) <- 1:10
ovol <- map_values(vol, lookup)

## Lookup table is a matrix. The first column is the key, and the second column is the value
names(lookup) <- 1:length(lookup)
lookup.mat <- cbind(as.numeric(names(lookup)), unlist(lookup))
ovol2 <- map_values(vol, lookup.mat)
all.equal(as.vector(ovol2), as.vector(ovol))

bbuchsbaum/neuroim2 documentation built on Feb. 26, 2025, 3:49 p.m.