Mutate Existing Variables

Example with the temperature dataset

Another common transformation of data is to create/compute new variables based on existing ones. For example, lets say we’re more comfortable thinking of temperature in degrees Celsius (°C) instead of degrees Fahrenheit (°F). The formula to convert temperatures from °F to °C is:

We can apply this formula to the temp variable using the mutate() function from the dplyr package, which takes existing variables and mutates them to create new ones.

Example with the weather dataset

For example, let’s consider the weather data frame to apply the mutate() function:

In this code, we mutate() the weather data frame by creating a new variable temp_in_C = (temp - 32) / 1.8) and then overwrite the original weather data frame. Why did we overwrite the weather data frame instead of assigning the result to a ...