CODEWITHSUNDEEP
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Ophelie
Ophelie

Reputation: 713

R : Re-scale data

I'm using R and the cars data frame.

I want to do a test :

1/ Scale the "cars" data in cars.scale

2/ Unscale cars.scale in order to check if I recover "cars" data

I did this but it doesn't work

data(cars)
library(DMwR)
cars.scale<- scale(cars)
head(cars)
head(cars.scale)

original_data <- unscale(cars.scale, cars)

I obtain this error message :"Error in -centers : invalid argument to unary operator"

Could you please help me to understand what's wrong ?

Upvotes: 1

Views: 2648

Answers (1)

jazzurro
jazzurro

Reputation: 23574

If you read the CRAN manual, you have the answer there. The first argument in the function is "a numeric matrix with the values to un-scale", which is cars.scale. The second argument is "an object to which the function scale() was applied", which is also cars.scale.

original_data <- unscale(cars.scale, cars.scale)

#      speed dist
# [1,]     4    2
# [2,]     4   10
# [3,]     7    4
# [4,]     7   22
# [5,]     8   16

From the CRAN manual

unscale(vals, norm.data, col.ids)

Arguments

vals A numeric matrix with the values to un-scale


norm.data A numeric and scaled matrix. This should be an object to which the function scale() was applied.

col.ids The columns of the vals matrix that are to be un-scaled (defaults to all of them).

Upvotes: 1

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