Add chapter 1 exercises

oslyman · repl.it user · commit 264dd2ec953e · 2020-05-29T22:20:55.000Z
diff --git a/.replit b/.replit
@@ -0,0 +1,2 @@
+language = "python3"
+run = ""
diff --git a/Work/bounce.py b/Work/bounce.py
@@ -1,3 +1,6 @@
 # bounce.py
 #
 # Exercise 1.5
+
+for i in range(10):
+  print(str(i + 1) + ' ' + str(round(60.0 * .6**i, 4)))
diff --git a/Work/mortgage.py b/Work/mortgage.py
@@ -1,3 +1,30 @@
 # mortgage.py
 #
-# Exercise 1.7
+# Exercises 1.7-11, 1.18
+
+principal = 500000.0
+rate = 0.05
+payment = 2684.11
+total_paid = 0.0
+month = 0
+extra_payment_start_month = 60
+extra_payment_end_month = 108
+extra_payment = 1000
+
+while principal > 0:
+    monthly_payment = payment
+    if month >= extra_payment_start_month and month < extra_payment_end_month:
+        monthly_payment += extra_payment
+    month += 1
+    if monthly_payment > principal:
+        total_paid += principal
+        principal = 0
+        print(f'{month} {round(total_paid, 2):6.2f} {round(principal, 2):6.2f}')
+        break
+
+    principal = principal * (1+rate/12) - monthly_payment
+    total_paid = total_paid + monthly_payment
+    print(f'{month} {round(total_paid, 2):6.2f} {round(principal, 2):6.2f}')
+
+print(f'Total paid {round(total_paid, 2):6.2f}')
+print(f'Total months {month}')
diff --git a/Work/pcost.py b/Work/pcost.py
@@ -1,3 +1,24 @@
 # pcost.py
 #
-# Exercise 1.27
+# Exercise 1.27, 1.30-3
+import csv
+import sys
+
+def portfolio_cost(filename):
+    total_cost = 0
+    with open(filename, 'rt') as f:
+        rows = csv.reader(f)
+        headers = next(rows)
+        for r in rows:
+            try:
+                total_cost += float(r[1]) * float(r[2])
+            except ValueError:
+                print("WARN: the csv file is missing a value, skipping this row")
+    return total_cost
+
+if len(sys.argv) == 2:
+    filename = sys.argv[1]
+else:
+    filename = 'Data/portfolio.csv'
+cost = portfolio_cost(filename)
+print(f'Total cost {round(cost, 2):0.2f}')
diff --git a/Work/sears.py b/Work/sears.py
@@ -0,0 +1,17 @@
+# sears.py
+#
+# Exercise 1.6
+
+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)

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,6 @@`
`1`	`1`	`# bounce.py`
`2`	`2`	`#`
`3`	`3`	`# Exercise 1.5`
	`4`	`+`
	`5`	`+for i in range(10):`
	`6`	`+ print(str(i + 1) + ' ' + str(round(60.0 * .6**i, 4)))`