Function

Description

as.character(); as.factor(); as.logical()

These are the functions to perform type conversion, such as as.numeric() seen in Chapter 2, Data Cleaning.

class()

This is used on an R object to determine the data type that the object is stored as.

encoding()

This reveals the encoding scheme that is used in storing the object.

grepl(); grep()

These are the functions in the base R package that use regular expressions to find instances of a search string.

gsub()

This is the function in the base R package that allows for global substitution of a string with another.

impute(x, fun = mean)

This is a function to impute a vector of values based on the average of existing values. This is used with x[is.na(x)] to isolate missing values.

install.packages()

This downloads and installs packages that are not included in Base R from CRAN-like repositories.

is.null()

This finds NULL variables that are simply empty items in an observation.

nrow(); ncol()

These are used to determine the number of rows or columns in a data frame.

read.table()

This is the underlying function of all other read functions. It is very flexible and is useful in tailoring how you read in data.

readlines()

This is useful for reading data that is raw text that is not in a tabular format.

strsplit()

This is useful when manipulating text data by splitting a string into substrings based on a separator value provided.