How to Use Date Formats in R

To format dates in R, use the format() function with various specifications. Having your dates in the proper format allows you to know that they are dates and which calculations should be performed on them.

Date formats

Getting a day

To get today’s date, use the Sys.Date() function.

To get the abbreviated day, pass the format “%a” to the format() function.

For a full day, pass the format argument to the “%A”.

For a weekday, pass the format argument to the “%u”.

# today date
today_date <- Sys.Date()

# Abbreviated Day
format(today_date, format = "%a")

# Full Day
format(today_date, format = "%A")

# Weekday
format(today_date, format = "%u")

# Output
# [1] "Sun"
# [1] "Sunday"
# [1] "0"

Getting a month

To extract the day from the date, pass format = “%d” to the format() function.

For the month number, pass the format argument to the “%m”.

For an abbreviated month, pass the format argument to the “%b”.

For getting full month name from the date, pass the format argument to the “%B”.

today_date <- Sys.Date()

# Default format yyyy-mm-dd
today_date

# Day
format(today_date, format = "%d")

# Month
format(today_date, format = "%m")

# Abbreviated month
format(today_date, format = "%b")

# Full month
format(today_date, format = "%B")


# Output:
# [1] "2023-12-24"
# [1] "24"
# [1] "12"
# [1] "Dec"
# [1] "December"
# [1] "12/24/23"
# [1] "24-Dec-23"

Getting the year

To extract the year from the date, pass format = “%y” to the format() function.

To get the year with the century, pass the format argument to the “%Y”.

To get the only century, pass the format argument to the “%C”.

today_date <- Sys.Date()

# Only year
format(today_date, format = "%y")

# Year with Century
format(today_date, format = "%Y")

# Only Century
format(today_date, format = "%C")

# Output:
# [1] "23"
# [1] "2023"
# [1] "20"

That’s it!