group data by levels of column
{dplyr}
count unique values of variables
{plyr}
change order of rows based on values of columns
{dplyr}
remove grouping
{dplyr}
apply function to columns and return TRUE if any values are TRUE
{dplyr}
return current group size
{dplyr}
summarize data usually by grouping variable
{dplyr}
drop rows containing missing values
{tidyr}
keep rows based on values of columns
{dplyr}
order in descending order
{dplyr}
count unique values of variables
{dplyr}
apply transformation across multiple columns
{dplyr}
The end!