R4DS-2e Ch. 19

tibble()

{tibble}

create tibble

inner_join()

{dplyr}

join two data sets keeping the observations that they have in common

count()

{dplyr}

count unique values of variables

between()

{dplyr}

determine if values in a numeric vector fall in specified range

tribble()

{tibble}

create row-wise tibble

filter()

{dplyr}

keep rows based on values of columns

ymd()

{lubridate}

parse dates with year, month, and day components

distinct()

{dplyr}

select only unique/distinct rows from data frame

left_join()

{dplyr}

join two data sets keeping the observations in the left one

library()

{base}

load R packages

year()

{lubridate}

return or set year component of a date-time

anti_join()

{dplyr}

join two data sets dropping all observations in x that have a match in y

head()

{utils}

return first rows of matrix, data frame, etc.

row_number()

{dplyr}

rank vector elements with ties set to first

sample()

{base}

randomly sample from vector

semi_join()

{dplyr}

join two data sets keeping all observations in x that have a match in y

select()

{dplyr}

keep specified columns

n()

{dplyr}

return current group size

is.na()

{base}

determine whether elements of vector are missing

full_join()

{dplyr}

join two data sets keeping the observations in both

c()

{base}

create vector of numbers, characters, etc.

mutate()

{dplyr}

create or modify data columns

The end!