generate: Attribute Creation
In tera-insights/gtBase: R Interface for the Grokit System

Description Usage Arguments Details Value Author(s) Examples

Generate appends columns to each row of the data by evaluating the given expression

1	Generate(x, ...)

`x`	an object of class `"data"`
`...`	a list of `name = expression` pairs. It is required that every argument to be named, as that name is used as the column name for the generated data.

It is important to note that generation adds overhead to the evaluation process. Creating an additional attribute solely for use in a single GLA or filtering is discouraged because of this. Generate is more appropiately used in conjunction with either joining, writing to the disc, or several actions using the same new attribute. See ‘examples’ below for more information.

An object of class "data" with the additonal columns.

Jon Claus at Tera Insights LLC

## inefficient usage
data <- Read(lineitem100g)
data <- Generate(data, cost = l_extended_price * (1 + l_tax) * (1 -
l_discount))
data <- data[cost < 100]

## this is also inefficient
data <- Read(lineitem100g)
data <- Generate(data, cost = l_extended_price * (1 + l_tax) * (1 -
l_discount), stock = l_quantity * l_extended_price)
data <- data[cost < 100]
data <- data[stock > 10]

## advised usage
supplier <- Read(supplier100g)
lineitem <- Read(lineitem100g)
lineitem <- Generate(lineitem, stock = l_quantity * l_extended_price)
data <- Join(supplier, s_acctbal, lineitem, stock)