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Only planets with rings

You will often want to select an entire column, namely one specific variable from a data frame. If you want to select all elements of the variable diameter, for example, both of these will do the trick:

planets_df[,3]
planets_df[,"diameter"]

However, there is a short-cut. If your columns have names, you can use the $ sign:

planets_df$diameter

This exercise is part of the course

Introduction to R

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Exercise instructions

  • Use the $ sign to select the rings variable from planets_df. Store the vector that results as rings_vector.
  • Print out rings_vector to see if you got it right.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# planets_df is pre-loaded in your workspace

# Select the rings variable from planets_df
rings_vector <- 
  
# Print out rings_vector
Edit and Run Code