Extract year from date

Question

How can I remove the first elements from a variable, especially if this variable has a special characters. For example, I have the following column:

Date 01/01/2009 01/01/2010 01/01/2011 01/01/2012 

I need to have a new column like the following:

Date 2009 2010 2011 2012 

Answer 1

As discussed in the comments, this can be achieved by converting the entry into Date format and extracting the year, for instance like this:

format(as.Date(df1$Date, format="%d/%m/%Y"),"%Y") 

Answer 2

library(lubridate) a=mdy(b) year(a) 

https://cran.r-project.org/web/packages/lubridate/vignettes/lubridate.html http://vita.had.co.nz/papers/lubridate.pdf