r_dataframes

Question 1

Create a data frame named “planets_df” with the following vectors:

• name,
• type,
• diameter,
• rotation,
• rings

Answer 1

planets_df <- data.frame(name, type, diameter, rotation, rings)

Question 2

Examine the structure of the “planets_df”

Answer 2

str(planets_df)

Question 3

For the data frame “planets_df”, print out the following:

1. The diameter of Mercury: this is the value at the first row and the third column.
2. From planets_df, select all data on Mars (the fourth row).
3. The first 5 values in the “diameter” column of planets_df

Answer 3

1. planets_df[1,3]
2. planets_df[4,]
3. planets_df[1:5, “diameter”]

Question 4

1. Select the “rings” variable from “planets_df”. Store the vector that results as rings_vector.
2. Select all columns for planets with rings
3. Do this with the subset function

Answer 4

1. rings_vector <- planet_df$rings
2. planets_df[rings_vector,]
3. subset(planet_df, subset = rings)

Question 5

Adapt the code so that instead of only the name column, all columns for planets that have rings are selected.

Answer 5

planets_df[rings_vector,]