View the pitching data.table (created in Quiz 4.3) like a spreadsheet
View(pitching)
Read in the Salaries CSV dataset directly from the following link and save it to a variable called "salaries"- http://dgrtwo.github.io/pages/lahman/Salaries.csv
salaries = read.csv("http://dgrtwo.github.io/pages/lahman/Salaries.csv")
Turn the salaries data.frame into a data.table (called "salaries")
salaries = as.data.table(salaries)
View the salaries data.table like a spreadsheet
View(salaries)
What column or columns are shared between the pitching and salaries data.tables? (Separate columns names with ",")
playerID,yearID,teamID,lgID
Merge the pitching and salaries data.tables, saving them into a data.table called "merged", using all the columns that are shared between the tables
merged = merge(pitching, salaries, by=c("lgID", "playerID", "teamID", "yearID"))
Merge the pitching and salaries data.tables, but this time keep all rows of the pitching data.table, including those that don't have salary information. Save this into a variable called "merged.all"
merged.all = merge(pitching, salaries, by=c("lgID", "playerID", "teamID", "yearID"), all.x=TRUE)