finish chapter 01 exercises

sguberman · sguberman · commit 5ae276e7f939 · 2020-06-19T19:25:43.000Z
diff --git a/Work/bounce.py b/Work/bounce.py
@@ -1,3 +1,10 @@
 # bounce.py
 #
 # Exercise 1.5
+
+height = 100
+bounce_efficiency = 3/5
+
+for bounce in range(1, 11):
+    height = height * bounce_efficiency
+    print(bounce, round(height, 4))
diff --git a/Work/mortgage.py b/Work/mortgage.py
@@ -1,3 +1,30 @@
 # mortgage.py
 #
 # Exercise 1.7
+
+principal = 500000.0
+rate = 0.05
+base_payment = 2684.11
+total_paid = 0.0
+month = 0
+
+# Extra payments
+extra_payment_start_month = 60
+extra_payment_end_month = 108
+extra_payment = 1000
+
+while principal > 0:
+    if month in range(extra_payment_start_month, extra_payment_end_month):
+        payment = base_payment + extra_payment
+    else:
+        payment = base_payment
+    principal = principal * (1 + rate/12) - payment
+    if principal < 0:
+        payment += principal
+        principal = 0
+    total_paid = total_paid + payment
+    month += 1
+    print(f'{month:>3d} {total_paid:>10.2f} {principal:>10.2f}')
+
+print('Total paid', round(total_paid, 2))
+print('Months', month)
diff --git a/Work/pcost.py b/Work/pcost.py
@@ -1,3 +1,31 @@
 # pcost.py
 #
 # Exercise 1.27
+
+import csv
+import sys
+
+
+def portfolio_cost(filename):
+    total = 0
+
+    with open(filename, 'rt') as f:
+        portfolio = csv.reader(f)
+        headers = next(portfolio)
+        for row in portfolio:
+            try:
+                symbol, shares, price = row
+                total += int(shares) * float(price)
+            except ValueError:
+                print(f'Error parsing row: {row} ... Skipping...')
+
+    return total
+
+
+if len(sys.argv) == 2:
+    filename = sys.argv[1]
+else:
+    filename = 'Data/portfolio.csv'
+
+cost = portfolio_cost(filename)
+print(f'Total cost: ${cost:>7.2f}')
diff --git a/Work/sears.py b/Work/sears.py
@@ -0,0 +1,14 @@
+# sears.py
+bill_thickness = 0.11 * 0.001  # Meters (0.11 mm)
+sears_height = 442  # Height (meters)
+num_bills = 1
+day = 1
+
+while num_bills * bill_thickness < sears_height:
+    print(day, num_bills, num_bills * bill_thickness)
+    day = day + 1
+    num_bills = num_bills * 2
+
+print('Number of days', day)
+print('Number of bills', num_bills)
+print('Final height', num_bills * bill_thickness)
