Merging Data Frames

• Merge two data frames that share a common column

live notes

123 GO – What’s your word of the day?

Announcements:

• Submit final project highlight separately from final project on Sunday.
• Evaluate this course.

Merging

Suppose I know which country a person is from, and I want to greet them using a greeting based on the language of their country. If we had a column representing the greeting for each person, then we could just use paste.

people = read.csv(text = "name,country
Clark,US
Jen,US
Sara,Mexico
Antonio,Honduras
Alexander,Russia
Sofia,Russia")

country = read.csv(text = "country,language
US,English
Russia,Russian
Mexico,Spanish
Honduras,Spanish")

greeting = read.csv(text = "language,greeting
English,hello
Spanish,hola
Korean,안녕
Russian,Здравствуйте")

We can merge country and greeting together based on the common column names. This does a database style join.

country_greeting = merge(country, greeting)
people2 = merge(people, country_greeting)

with(people2, paste(greeting, name))