Julia for Data Science (Video 14)

This video tutorial explores the use of dataframes in data analysis, focusing on importing datasets, using various functions to explore and subset data, applying functions to columns and rows, grouping data by features, and sorting and stacking data. The tutorial uses the iris dataset as an example and demonstrates techniques such as conditional selection, applying aggregate functions, and reverse sorting.

What is the first step to access classical datasets in R?

• Use the summary function

• Download the dataset

• Create a new data frame

• Import the package

Which function provides a quick insight into the type and size of a dataset?

• names

• head

• tail

• summary

How can you access a column of measurements in a data frame?

• By using the column's name

• By using the row's index

• By using the row's name

• By using the column's index

Which function is used to find distinct values in a column?

• unique

• sort

• aggregate

• group by

What operator is used for element-wise comparison in data frames?

• ==

• !=

• ===

• !==

Which function is used to apply a function to grouped data?

• unique

• sort

• filter

• aggregate

How can you sort data in reverse order?

• Add Rev = true

• Use the sort function

• Add Desc = true

• Use the unique function