दिन 4: Conditions, Loops और Functions

credit_score = 712
if credit_score >= 750:
    band = "Low risk"
elif credit_score >= 650:
    band = "Medium risk"
else:
    band = "High risk"
print(credit_score, "->", band)

amount, is_member = 2400, True
shipping = 0 if amount >= 499 else 40            # one-line if
discount = 0.10 if is_member and amount > 2000 else 0
print("Shipping:", shipping, "| Discount:", discount)

orders = [1499, 299, 15999, 649, 2499]
total = 0
for amount in orders:
    total += amount
print("Total:", total, "| Orders:", len(orders), "| Average:", total / len(orders))

cities = ["Delhi", "Mumbai", "Pune"]
sales = [125000, 98000, 64000]
for i, city in enumerate(cities, start=1):
    print(i, city)
for city, amt in zip(cities, sales):
    print(f"{city:8} ₹{amt:,}")
for month in range(1, 13, 3):
    print("Quarter starts in month", month)

temps = [31, 33, 36, 41, 39, 44, 29]
for day, t in enumerate(temps, 1):
    if t < 35:
        continue                  # skip normal days
    if t >= 44:
        print("Day", day, ": heat-wave alert! stop checking")
        break
    print("Day", day, ": hot", t)

balance, emi, month = 120000, 15500, 0     # loan payoff
while balance > 0:
    balance -= emi
    month += 1
print("Loan finished in", month, "months; extra paid:", -balance)

prices = [499, 1299, 2499, 89, 15999]
with_gst = [round(p * 1.18) for p in prices]
premium = [p for p in prices if p > 1000]
labels = ["High" if p > 2000 else "Low" for p in prices]
print(with_gst)
print(premium)
print(labels)

def risk_band(score, income):
    """Return the risk band of a loan applicant."""
    if score >= 750 and income >= 50000:
        return "Low"
    elif score >= 650:
        return "Medium"
    return "High"

applicants = [(780, 85000), (700, 30000), (610, 90000)]
for s, inc in applicants:
    print(s, inc, "->", risk_band(s, inc))

def final_price(price, discount=0.0, gst=0.18):
    """Price after discount, then GST."""
    return round(price * (1 - discount) * (1 + gst), 2)

print(final_price(1000))                    # default discount and gst
print(final_price(1000, discount=0.2))
print(final_price(1000, 0.1, gst=0.05))

def summary(numbers):
    """Return several statistics at once (a tuple)."""
    return min(numbers), max(numbers), sum(numbers) / len(numbers)

low, high, avg = summary([42, 77, 58, 91, 66])
print(f"min {low}, max {high}, avg {avg:.1f}")
square = lambda x: x * x                    # tiny one-line function
print(sorted(["Pune", "Agra", "Delhi"], key=lambda c: len(c)))
print(square(12))

def grade(avg):
    if avg >= 90: return "A1"
    if avg >= 80: return "A2"
    if avg >= 70: return "B1"
    if avg >= 60: return "B2"
    if avg >= 33: return "C"
    return "Fail"

students = {"Aman": [88, 92, 79], "Priya": [95, 97, 91], "Rahul": [45, 30, 52], "Sneha": [72, 68, 75]}
counts = {}
for name, marks in students.items():
    avg = sum(marks) / len(marks)
    g = grade(avg)
    counts[g] = counts.get(g, 0) + 1
    print(f"{name:6} avg {avg:5.1f}  grade {g}")
print("Grade count:", counts)