R4DS-2e Ch. 27

summarize()

{dplyr}

summarize data usually by grouping variable

select()

{dplyr}

keep specified columns

rbind()

{base}

bind rows in base R

order()

{base}

return index of sorted vector (base R)

c()

{base}

create vector of numbers, characters, etc.

max()

{base}

compute maxima of input values

seq_along()

{base}

return a sequence along the length of an object

data.frame()

{base}

create data frame

map()

{purrr}

apply a function to multiple elements of an object in purrr, return a list

group_by()

{dplyr}

group data by levels of column

pull()

{dplyr}

extract a single column

arrange()

{dplyr}

change order of rows based on values of columns

vector()

{base}

create a vector

tibble()

{tibble}

create tibble

read_excel()

{readxl}

import either xls or xlsx Excel files

sapply()

{base}

apply a function to multiple elements of an object and return a vector, matrix, or array

library()

{base}

load R packages

vapply()

{base}

apply a function to multiple elements of an object and return a vector

runif()

{stats}

generate random number from uniform distribution

str()

{utils}

return object structure

mean()

{base}

calculate mean of elements of vector

tapply()

{base}

apply a function to each cell of a ragged array

is.numeric()

{base}

determine if input is of type numeric

list()

{base}

create recursive vector (list)

lapply()

{base}

apply a function to multiple elements of an object and return a list

dir()

{base}

return directories in named directory

cut()

{base}

divide range of vector into intervals

length()

{base}

return number of elements in a vector

levels()

{base}

view and change factor levels

is.na()

{base}

determine whether elements of vector are missing

filter()

{dplyr}

keep rows based on values of columns

The end!