R: xts get year or month for a certain row in a xts time series object

Question

How can I get for example the year of the first or last entry in a xts time series object as a string? In this example of the AAPL time series?

require(quantmod)
getSymbols("AAPL")

Answer 1

Year of first entry....

format(index(first(AAPL)),"%Y")

Year of last entry...

format(index(last(AAPL)),"%Y")