title: Is there a way in R to create a new column, assigning values conditional on other columns?
body: <p>I have a data frame with multiples dates and associated data/variables. I'm looking to create a new column in the data frame that assigns a Yes or No variable to the new column depending on the date of the other column. For example, all dates before, say, Date1 need a 'Yes' in the new column, and all dates after Date1 need a 'No' in the new column. How do I do this?</p>