polypoly (version 0.0.2)

poly_add_columns: Add orthogonal polynomial columns to a dataframe

Description

Add orthogonal polynomial columns to a dataframe

Usage

poly_add_columns(.data, .col, degree = 1, prefix = NULL,
  scale_width = NULL)

Value

the dataframe with additional columns of orthogonal polynomial terms of .col

Arguments

.data

a dataframe

.col

a bare column name

degree

number of polynomial terms to add to the dataframe

prefix

prefix for the names to add to the dataframe. default is the name of .col.

scale_width

optionally rescale the dataframe using poly_rescale(). Default behavior is not to perform any rescaling.

Examples

df <- data.frame(time = rep(1:5, 3), y = rnorm(15))

# adds columns "time1", "time2", "time3"
poly_add_columns(df, time, degree = 3)

# adds columns "t1", "t2", "t3 and rescale
poly_add_columns(df, time, degree = 3, prefix = "t", scale_width = 1)