Simplify read_portfolio function with list comprehension

Quest10 · Quest10 · commit a27b5656473a · 2021-04-18T16:50:55.000+02:00
diff --git a/Work/report.py b/Work/report.py
@@ -1,23 +1,20 @@
 # report.py
 #
-# Exercise 2.16 - Use method dict/zip for a flexible reading of csv
-
+# Exercise 2.23 - Simplify read_portfolio with list comprenhesion
+# Extra feature: read_portfolio can read from csv with unwanted columns
 
 import csv
 
 def read_portfolio(filename):
     '''Return portfolio in list of dictionaries''' 
-    portfolio = [ ]
 
     with open(filename, 'rt') as f:
         rows = csv.reader(f)
         headers = next(rows)
-        for row in rows:
-            # If we use dict+zip we broke script because all fields will be strings
-            # We need to cast field in 44 line to operate as a float
-            holding = dict(zip(headers, row))
-            #holding = {"name": row[0], "shares":int(row[1]), "price":float(row[2])}
-            portfolio.append(holding)
+        # Select on all CSV same columns
+        select = ['name', 'shares', 'price']
+        indices = [ headers.index(colname) for colname in select ]
+        portfolio = [ { colname: row[index] for colname, index in zip(select, indices) } for row in rows ]
     return portfolio
 
 def read_prices(filename):
@@ -60,7 +57,7 @@ def get_headers(report):
 
 
 prices = read_prices('Data/prices.csv')
-portfolio = read_portfolio('Data/portfolio.csv')
+portfolio = read_portfolio('Data/portfoliodate.csv')
 report = make_report(portfolio, prices)
 
     
