dlookr (version 0.4.5)

transform: Data Transformations

Description

Performs variable transformation for standardization and resolving skewness of numerical variables.

Usage

transform(
  x,
  method = c("zscore", "minmax", "log", "log+1", "sqrt", "1/x", "x^2", "x^3",
    "Box-Cox", "Yeo-Johnson")
)

Arguments

x

numeric vector for transformation.

method

method of transformations.

Value

An object of transform class. Attributes of transform class is as follows.

• method : method of transformation data.

  • Standardization

    • "zscore" : z-score transformation. (x - mu) / sigma

    • "minmax" : minmax transformation. (x - min) / (max - min)

  • Resolving Skewness

    • "log" : log transformation. log(x)

    • "log+1" : log transformation. log(x + 1). Used for values that contain 0.

    • "sqrt" : square root transformation.

    • "1/x" : 1 / x transformation

    • "x^2" : x square transformation

    • "x^3" : x^3 square transformation

    • "Box-Cox" : Box-Box transformation

    • "Yeo-Johnson" : Yeo-Johnson transformation

Details

transform() creates an transform class. The `transform` class includes original data, transformed data, and method of transformation.

See vignette("transformation") for an introduction to these concepts.

See Also

summary.transform, plot.transform.

Examples

# NOT RUN {
# Standardization ------------------------------
creatinine_minmax <- transform(heartfailure$creatinine, method = "minmax")
creatinine_minmax
summary(creatinine_minmax)
plot(creatinine_minmax)

# Resolving Skewness  --------------------------
creatinine_log <- transform(heartfailure$creatinine, method = "log")
creatinine_log
summary(creatinine_log)

# plot(creatinine_log)

# plot(creatinine_log, typographic = FALSE)

# Using dplyr ----------------------------------
library(dplyr)

heartfailure %>%
  mutate(creatinine_log = transform(creatinine, method = "log+1")) %>%
  lm(sodium ~ creatinine_log, data = .)
  
# }