Step 5: Print a clear report

Numbers are only useful if people can read them. Build a small table with an f-string for each row: a header, a rule line, one row per region sorted by revenue, and a total row. A money() helper formats thousands separators and the dollar sign in one place.

Examplepython

import csv, io

RAW = """date,region,product,units,price
2026-01-05,North,Notebook,10,4.50
2026-01-09,South,Pen,50,1.20
2026-01-12,North,Backpack,3,39.90
2026-01-15, East ,Notebook,8,4.50
2026-02-01,South,Headphones,2,59.00
2026-02-03,West,Pen,n/a,1.20
2026-02-10,North,Pen,40,1.20
2026-02-14,East,Backpack,5,39.90
2026-02-20,,Mouse,4,19.50
2026-03-02,South,Notebook,12,4.50
2026-03-09,West,Headphones,3,59.00
2026-03-15,North,Mouse,6,19.50
2026-03-21,East,Pen,30,1.20"""

def clean(raw_rows):
    good = []
    for r in raw_rows:
        try:
            units, price = int(r["units"]), float(r["price"])
        except ValueError:
            continue
        if not r["region"].strip():
            continue
        good.append({"date": r["date"], "region": r["region"].strip(), "product": r["product"].strip(),
                     "units": units, "price": price, "revenue": round(units * price, 2)})
    return good

sales = clean(csv.DictReader(io.StringIO(RAW)))

from collections import defaultdict

def money(x):
    return f"${x:,.2f}"

by_region = defaultdict(lambda: {"orders": 0, "units": 0, "revenue": 0.0})
for s in sales:
    r = by_region[s["region"]]
    r["orders"] += 1
    r["units"] += s["units"]
    r["revenue"] += s["revenue"]

print(f'{"Region":<8}{"Orders":>7}{"Units":>7}{"Revenue":>12}')
print("-" * 34)
for name, r in sorted(by_region.items(), key=lambda kv: -kv[1]["revenue"]):
    print(f"{name:<8}{r['orders']:>7}{r['units']:>7}{money(r['revenue']):>12}")
print("-" * 34)
print(f"{'Total':<8}{sum(r['orders'] for r in by_region.values()):>7}{sum(r['units'] for r in by_region.values()):>7}{money(sum(r['revenue'] for r in by_region.values())):>12}")

Open in editor »

Formatting helpers like money keep your code tidy: if the manager wants euros, you change one function.

Your turn: write the code

Write money(x) that formats a number with a dollar sign, thousands separators and two decimals. Print money(1234.5) and money(0.5).

Quick check

What does the format :,.2f do?

Adds thousands separators and two decimalsRounds to whole numbersPads with zeros

Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.

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