Exercise 7.11

aprell · aprell · commit 50b24ee032b2 · 2020-08-08T15:06:05.000+02:00
diff --git a/Work/portfolio.py b/Work/portfolio.py
@@ -1,8 +1,12 @@
 # Exercises 6.2, 6.3, 6.14
+# Exercise 7.11
+
+from fileparse import parse_csv
+from stock import Stock
 
 class Portfolio:
-    def __init__(self, holdings):
-        self._holdings = holdings
+    def __init__(self):
+        self._holdings = []
 
     def __iter__(self):
         return iter(self._holdings)
@@ -16,6 +20,28 @@ def __getitem__(self, index):
     def __contains__(self, name):
         return any(name == holding.name for holding in self._holdings)
 
+    def append(self, holding):
+        if not isinstance(holding, Stock):
+            raise TypeError("Expected a Stock instance")
+        self._holdings.append(holding)
+
+    @classmethod
+    def from_csv(cls, lines, **opts):
+        self = cls()
+
+        portfolio = parse_csv(
+            lines,
+            has_headers=True,
+            select=["name", "shares", "price"],
+            types={"shares": int, "price": float},
+            **opts
+        )
+
+        for holding in portfolio:
+            self.append(Stock(**holding))
+
+        return self
+
     @property
     def total_cost(self):
         return sum(holding.cost for holding in self._holdings)
diff --git a/Work/report.py b/Work/report.py
@@ -5,11 +5,10 @@
 # Exercises 4.3-4.8
 # Exercise 5.6
 # Exercise 6.2
-# Exercises 7.3, 7.4
+# Exercises 7.3, 7.4, 7.11
 
 from fileparse import parse_csv
 from portfolio import Portfolio
-from stock import Stock
 from tableformat import create_formatter
 import sys
 
@@ -27,16 +26,7 @@ def read_prices(filename, **opts):
 
 def read_portfolio(filename, **opts):
     with open(filename, "rt") as file:
-        portfolio = parse_csv(
-            file,
-            has_headers=True,
-            select=["name", "shares", "price"],
-            types={"shares": int, "price": float},
-            **opts
-        )
-    return Portfolio([
-        Stock(**holding) for holding in portfolio
-    ])
+        return Portfolio.from_csv(file, **opts)
 
 def make_report(portfolio, prices):
     report = []
