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05beginner

DataFrame GroupBy & Aggregation

Group rows by one or more columns and aggregate each group, like SQL GROUP BY.

What you will learn

  • Use deepbox/dataframe for DataFrame, groupBy, agg, getGroup, nunique.
  • Group rows by one or more columns and aggregate each group, like SQL GROUP BY.

Source

index.ts
/** * Example 05: DataFrame GroupBy & Aggregation * * Group rows by one or more columns and aggregate each group, like SQL GROUP BY. */ import { DataFrame } from "deepbox/dataframe"; console.log("=== DataFrame GroupBy & Aggregation ===\n"); // Create sample sales dataconst sales = new DataFrame({  product: ["Laptop", "Mouse", "Laptop", "Keyboard", "Mouse", "Laptop", "Keyboard", "Mouse"],  region: ["North", "North", "South", "North", "South", "North", "South", "South"],  quantity: [5, 20, 3, 15, 25, 4, 10, 30],  revenue: [5000, 400, 3000, 450, 500, 4000, 300, 600],}); // Display the raw dataconsole.log("Sales Data:");console.log(`${sales.toString()}\n`); // Group by one column and sum two othersconsole.log("Group by a single column");const byProduct = sales.groupBy("product");const productStats = byProduct.agg({  quantity: "sum",  revenue: "sum",}); console.log("Sales by Product:");console.log(`${productStats.toString()}\n`); // Group by region and take the mean of each numeric columnconst byRegion = sales.groupBy("region");const regionStats = byRegion.agg({  quantity: "mean",  revenue: "mean",}); console.log("Average Sales by Region:");console.log(`${regionStats.toString()}\n`); // Use a different function per columnconsole.log("Different function per column");const detailedStats = byProduct.agg({  quantity: "sum",  revenue: "mean",}); console.log("Total quantity and mean revenue by product:");console.log(`${detailedStats.toString()}\n`); // Named aggregation: the key is the output column, the value is [column, function]console.log("Named aggregation");const named = byProduct.agg({  unitsSold: ["quantity", "sum"],  avgRevenue: ["revenue", "mean"],  orders: ["revenue", "count"],});console.log(`${named.toString()}\n`); // Group by two columnsconsole.log("Group by two columns");console.log(`${sales.groupBy(["product", "region"]).agg({ revenue: "sum" }).toString()}\n`); // Pull out the rows of a single groupconsole.log("Rows of the Laptop group:");console.log(`${byProduct.getGroup("Laptop").toString()}\n`); // Number of distinct values per groupconsole.log("Distinct values per product:");console.log(byProduct.nunique().toString());

Output

Console output
Console output only.