How to Check if a Column is a Date in R: A Comprehensive Guide with Examples


Steven P. Sanderson II, MPH


February 8, 2024


As an R programmer, you may often encounter datasets where you need to determine whether a column contains date values. This task is crucial for data cleaning, manipulation, and analysis. In this blog post, we’ll explore various methods to check if a column is a date in R, with a focus on using the lubridate package and the ts_is_date_class() function from the healthyR.ts package.


Using lubridate

lubridate is a powerful package in R for handling date and time data. It provides intuitive functions to parse, manipulate, and work with date-time objects. Let’s see how we can use lubridate to check if a column is a date.

# Load the lubridate package

# Sample data frame
df <- data.frame(
  Date_Column = c("2022-01-01", "2022-02-15", "not a date", "2022-03-30")

# Check if Date_Column is a date
is_date <- is.Date(df$Date_Column)

# Print the result

In this example, we created a sample data frame df with a column named Date_Column. We used the is.Date() function from lubridate to check if the values in Date_Column are dates. The result is a logical with either a value of (TRUE) or (FALSE). In this instance the result is FALSE because the entire vector is not a date. This can change to TRUE if the entire vector is a date. See below:

df |> 
  mutate(Date_Column = as.Date(Date_Column)) |> 
  pull(Date_Column) |> 
[1] TRUE
# OR
df |>
  mutate(Date_Column = as.Date(Date_Column) |> is.Date())
1        TRUE
2        TRUE
3        TRUE
4        TRUE

Using ts_is_date_class() from healthyR.ts

Now, let’s explore how to achieve the same task using the ts_is_date_class() function from the healthyR.ts package. This function is specifically designed to check if a column is a date class, providing an alternative method for date validation.

# Install and load the healthyR.ts package
# install.packages("healthyR.ts")

# Check if Date_Column is a date using ts_is_date_class()
is_date_class <- ts_is_date_class(as.Date(df$Date_Column))

# Print the result
[1] TRUE
# OR

df |>
  mutate(is_date = ts_is_date_class(as.Date(Date_Column)))
  Date_Column is_date
1  2022-01-01    TRUE
2  2022-02-15    TRUE
3  not a date    TRUE
4  2022-03-30    TRUE

In this example, we installed and loaded the healthyR.ts package, which contains the ts_is_date_class() function. We then applied this function to df$Date_Column to check if the values are of date class.

You will notice both methods incorrectly identify the row “not a date” as a date because the as.Date() function coerces the string “not a date” to an NA inside of the mutate function. If you use rowwise() before the mutate it will fail out completely, this can be a pitfall and is something to watch out for.


Now that you’ve seen two different methods to check if a column is a date in R, I encourage you to try them out with your own datasets. Whether you prefer using lubridate or the functions from the healthyR.ts package, understanding how to validate date columns is essential for efficient data analysis and manipulation. See what you come up with!

Experiment with different datasets and column types to gain a deeper understanding of these techniques. By mastering these skills, you’ll become more proficient in handling date and time data in R, empowering you to tackle a wide range of data analysis tasks effectively.

In conclusion, checking if a column is a date in R is a fundamental skill for data professionals. With the right tools and techniques, such as those provided by lubridate and healthyR.ts, you can confidently validate date columns in your datasets and streamline your data analysis workflows.

Happy coding, and may your data always be accurate and insightful!

That wraps up our exploration of how to check if a column is a date in R. I hope you found this post helpful and informative. Stay tuned for more R programming tips and tutorials!