Data Engineering with Polars: Performing Upserts (Merge) into Delta Tables
In Data Engineering, you rarely just “write” files. You usually have a master dataset (e.g., “All Users”), and every day you get a “Daily Update”…
Merging DataFrames in Pandas: A Guide to merge() and concat()
Real-world data is rarely in one single file. You might have sales data in one CSV and customer info in another. You need to combine…
