#aggregation code explainers

python

import re
from collections import defaultdict
from pathlib import Path

Summarizing log files by date in Python

regex parsing aggregation

Intermediate 7 steps

php

<?php
 
namespace App\Services;

Caching tenant dashboard metrics in Laravel

caching multi-tenancy aggregation

Intermediate 7 steps

python

import csv
from collections import defaultdict
from dataclasses import dataclass, field
from decimal import Decimal, InvalidOperation

Aggregating CSV sales by category in Python

dataclasses csv-parsing defaultdict

Intermediate 8 steps

java

public Map<Long, List<Order>> ordersByCustomer(List<Order> orders) {
    return orders.stream()
            .collect(Collectors.groupingBy(Order::getCustomerId));
}

Grouping streams with Java Collectors

streams grouping collectors

Intermediate 5 steps

typescript

interface Order {
  id: number;
  customerId: string;
  total: number;

A type-safe groupBy in TypeScript

generics reduce type-inference

Intermediate 6 steps

rust

use std::collections::HashMap;
 
#[derive(Debug, Clone)]
struct Order {

Aggregating Rust data with fold and entry

fold hashmap ownership

Intermediate 6 steps

python

from django.db.models import Sum, Count, F, DecimalField
from django.db.models.functions import TruncMonth, Coalesce
 
from .models import Order

Build a monthly revenue report in Django

aggregation orm group-by

Advanced 7 steps