Added solution code

Solutions/6_15/ticker.py

@@ -0,0 +1,44 @@
+# ticker.py
+
+import csv
+import report
+import tableformat
+from follow import follow
+import time
+
+def select_columns(rows, indices):
+    for row in rows:
+        yield [row[index] for index in indices]
+
+def convert_types(rows, types):
+    for row in rows:
+        yield [func(val) for func, val in zip(types, row)]
+
+def make_dicts(rows, headers):
+    return (dict(zip(headers,row)) for row in rows)
+
+def parse_stock_data(lines):
+    rows = csv.reader(lines)
+    rows = select_columns(rows, [0, 1, 4])
+    rows = convert_types(rows, [str,float,float])
+    rows = make_dicts(rows, ['name','price','change'])
+    return rows
+
+def ticker(portfile, logfile, fmt):
+    portfolio = report.read_portfolio(portfile)
+    lines = follow(logfile)
+    rows = parse_stock_data(lines)
+    rows = (row for row in rows if row['name'] in portfolio)
+    formatter = tableformat.create_formatter(fmt)
+    formatter.headings(['Name','Price','Change'])
+    for row in rows:
+        formatter.row([ row['name'], f"{row['price']:0.2f}", f"{row['change']:0.2f}"] )
+
+def main(args):
+    if len(args) != 4:
+        raise SystemExit('Usage: %s portfoliofile logfile fmt' % args[0])
+    ticker(args[1], args[2], args[3])
+
+if __name__ == '__main__':
+    import sys
+    main(sys.argv)