using {admisc}

Evaluate an expression in a data environment

Description

A function almost identical to the base function with(), but allowing to evaluate the expression in every subset of a split file.

Usage

using(data, expr, split.by = NULL, ...)

Arguments

data

A data frame.

expr

Expression to evaluate

split.by

A factor variable from the data, or a declared/labelled variable

...

Other internal arguments.

Value

A list of results, or a matrix if each separate result is a vector.

Author(s)

Adrian Dusa

Examples

set.seed(123)
DF <- data.frame(
    Area = factor(sample(c("Rural", "Urban"), 123, replace = TRUE)),
    Gender = factor(sample(c("Female", "Male"), 123, replace = TRUE)),
    Age = sample(18:90, 123, replace = TRUE),
    Children = sample(0:5, 123, replace = TRUE)
)


# table of frequencies for Gender
table(DF$Gender)

# same with
using(DF, table(Gender))

# same, but split by Area
using(DF, table(Gender), split.by = Area)

# calculate the mean age by gender
using(DF, mean(Age), split.by = Gender)

# same, but select cases from the urban area
using(subset(DF, Area == "Urban"), mean(Age), split.by = Gender)

# mean age by gender and area
using(DF, mean(Age), split.by = Area & Gender)

# same with
using(DF, mean(Age), split.by = c(Area, Gender))

# average number of children by Area
using(DF, mean(Children), split.by = Area)

# frequency tables by Area
using(DF, table(Children), split.by = Area)