See how to join two data sets by one or more common columns using base R’s merge function, dplyr join functions, and the speedy data.table package. R has a number of quick, elegant ways to join ...

Microsoft Excel's Data Validation tool lets you add a drop-down list to a cell based on existing data in a column. However, how this works depends on whether the source data is part of a formatted ...

As a rule, data tables should be provided as data tables, especially when found in online assessments. Care should be taken to include proper HTML coding to make the tables readily navigable by a ...

“Hash tables are among the oldest data structures we have ... the last remaining open spot—is proportional to x. “If your hash table is 99 percent full,” Kuszmaul said, “it makes ...

For some data.table users, “dot-SD” is a bit of a mystery. But data.table creator Matt Dowle told me that it’s actually quite simple: Just think of it as a symbol representing “each group.” ...

In this example, you combine selected columns from two data sets and edit them in a new data table. This example assumes that you have no data set loaded in the Analyst data table. If you do, select ...