The Smart Chef

data.table cheat sheet

The benefits of using data.table in your R workflows.

The data.table package is an incredibly powerful tool for data manipulation in R. It is designed to handle large datasets quickly and efficiently, making it an ideal choice for tasks that involve millions of rows or more. The package offers a wide range of functions and features that allow you to perform a variety of data manipulation tasks with ease. Whether you need to filter, aggregate, or join your data, data.table has you covered. I personally perfer the structure and syntax of using data.table over using many of the same functions in the dplyr or the tidyverse. data.table is oftentimes found to be faster than similar tidyverse functions as well.

One of the biggest advantages of using data.table is its speed and efficiency. The package is optimized for performance, allowing you to perform complex operations on large datasets in a matter of seconds. This can be especially useful when working with data that would be impractical to process using other tools or packages. Additionally, data.table has a simple and intuitive syntax that makes it easy to learn and use. It offers a single data structure, the data.table, which makes it easy to perform complex data manipulations without having to switch between multiple functions. Overall, the data.table package is an incredibly useful tool for anyone working with large datasets or performing complex data manipulations in R.

Below are some of the highlights to the advantages to data.table, along with a cheat sheet to help with syntax:

  1. Speed and Efficiency. ne of the biggest advantages of using data.table is its speed and efficiency. data.table is designed to handle large datasets and perform operations on them quickly, making it a great tool for data manipulation tasks that involve millions of rows or more.
  2. Easy to Learn and Use. data.table has a simple syntax and is designed to be easy to learn and use. It uses a single data structure, the data.table, which makes it easy to perform complex data manipulations without having to switch between multiple functions.
  3. Flexibility and Functionality. data.table offers a wide range of functions and features that allow you to perform a variety of data manipulation tasks. It includes powerful filtering, aggregation, and join functions, as well as the ability to modify and create columns on the fly.
  4. Compatibility with Base R and Other Packages. data.table has a simple syntax and is designed to be easy to learn and use. It uses a single data structure, the data.table, which makes it easy to perform complex data manipulations without having to switch between multiple functions.

data.table Cheat Sheet

Action Code
Create a data.table DT <- data.table(df)
Select columns DT[, c("col1", "col2")]
Select rows DT[col1 > 5]
Subset rows and select columns DT[col1 > 5, c("col1", "col2")]
Order rows DT[order(col1)]
Group by and summarize DT[, .(mean_col1 = mean(col1)), by = group_col]
Join tables DT1[DT2, on = "key_col"]
Add columns DT[, new_col := col1 + col2]
Modify columns DT[, col1 := col1 + 1]
Delete columns DT[, col1 := NULL]

You can also combine these different methods to unlock even more functionality. For example, if you need to update the rows in a data.table, but only if a certain criteria is met, you can combine the "Select Rows" and "Modify Columns" logic

Action Code
Select Rows and update only those Rows: DT[col1 > 5, col1 := col1 + 1]