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Exercises/soln1_4.md

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+# Exercise 1.4 - Solution
+
+## (a) Defining a function
+
+```python
+# pcost.py
+
+def portfolio_cost(filename):
+    total_cost = 0.0
+    with open(filename) as f:
+        for line in f:
+            fields = line.split()
+            nshares = int(fields[1])
+            price = float(fields[2])
+            total_cost = total_cost + nshares * price
+    return total_cost
+
+print(portfolio_cost('Data/portfolio.dat'))
+```
+
+## (b) Adding some error handling
+
+```python
+# pcost.py
+
+def portfolio_cost(filename):
+    total_cost = 0.0
+    with open(filename) as f:
+        for line in f:
+            fields = line.split()
+            try:
+                nshares = int(fields[1])
+                price = float(fields[2])
+                total_cost = total_cost + nshares*price
+
+            # This catches errors in int() and float() conversions above
+            except ValueError as e:
+                print("Couldn't parse:", repr(line))
+                print("Reason:", e)
+    return total_cost
+
+print(portfolio_cost('Data/portfolio3.dat'))
+```
+
+
+[Back](ex1_4.md)