Feature/singelton (#15)

Small improvements

Uses generators as much as possible.
PyTickerSymbols is now a singleton because there is no need to hold more than one instance

.theia/settings.json

@@ -0,0 +1,8 @@
+{
+   "python.testing.pytestArgs": [
+      "tests"
+   ],
+   "python.testing.unittestEnabled": false,
+   "python.testing.nosetestsEnabled": false,
+   "python.testing.pytestEnabled": true
+}

setup.py

@@ -8,7 +8,8 @@
 from setuptools import setup, find_packages
 
 EXCLUDE_FROM_PACKAGES = ['test', 'test.*', 'test*']
-VERSION = '1.1.8'
+
+VERSION = '1.1.9'
 
 with open("README.md", "r") as fh:
     long_description = fh.read()

src/pytickersymbols/__init__.py

@@ -8,9 +8,20 @@
 import os
 import json
 
+class Singleton(type):
+    def __init__(cls, name, bases, my_dict):
+        super(Singleton, cls).__init__(name, bases, my_dict)
+        cls.instance = None
+
+    def __call__(cls,*args,**kw):
+        if cls.instance is None:
+            cls.instance = super(Singleton, cls).__call__(*args, **kw)
+        return cls.instance
 
 class PyTickerSymbols:
 
+    __metaclass__ = Singleton
+
     def __init__(self):
         self.__stocks = None
         json_path = os.path.join(
@@ -38,8 +49,10 @@ def get_all_countries(self):
         Returns all available countries
         :return: list of country names
         """
-        items = [stock["country"] for stock in self.__stocks["companies"]]
-        return list(set(items))
+        countries = set(
+            map(lambda stock: stock['country'], self.__stocks["companies"])
+        )
+        return countries
 
     def get_stocks_by_index(self, index):
         """
@@ -81,15 +94,10 @@ def get_stocks_by_country(self, country):
         :param country: name of country
         :return: list of stocks
         """
-
-        def __valid(cou, st_cou):
-            return isinstance(cou, str) and st_cou.lower() == cou.lower()
-
-        return [
-            stock
-            for stock in self.__stocks["companies"]
-            if __valid(country, stock["country"])
-        ]
+        return filter(
+            lambda stock: isinstance(country, str) and stock["country"].lower() == country.lower(),
+            self.__stocks["companies"]
+        )
 
     def index_to_yahoo_symbol(self, index_name):
         """
@@ -105,12 +113,16 @@ def index_to_yahoo_symbol(self, index_name):
         return yahoo_symbol
 
     def __get_items(self, key, val):
-        stocks = [
-            stock
-            for stock in self.__stocks["companies"]
-            for item in stock[key]
-            if isinstance(val, str) and val.lower() == item.lower()
-        ]
+        stocks =  filter(
+            lambda item: len(
+                list(
+                    filter(
+                        lambda sub_item: isinstance(val, str) and val.lower() == sub_item.lower(), item[key]
+                    )
+                )
+            ) > 0,
+            self.__stocks["companies"]
+        )
         return stocks
 
     def __get_sub_items(self, key):

tests/test_lib.py

@@ -13,6 +13,13 @@
 
 class TestLib(unittest.TestCase):
 
+    def test_singleton(self):
+        """
+        Test singleton pattern
+        :return:
+        """
+        self.assertTrue(id(PyTickerSymbols()) == id(PyTickerSymbols()))
+
     def test_index(self):
         """
         Test index getter
@@ -37,7 +44,7 @@ def test_encoding(self):
         """
         stock_data = PyTickerSymbols()
         self.assertIsNotNone(stock_data)
-        dax = stock_data.get_stocks_by_index('DAX')
+        dax = list(stock_data.get_stocks_by_index('DAX'))
         self.assertEqual(dax[10]['name'], 'Deutsche Börse AG')
 
 
@@ -48,7 +55,7 @@ def test_country(self):
         """
         stock_data = PyTickerSymbols()
         self.assertIsNotNone(stock_data)
-        countries = stock_data.get_all_countries()
+        countries = list(stock_data.get_all_countries())
         self.assertIsNotNone(countries)
         self.assertIn("Germany", countries)
         self.assertIn("Netherlands", countries)
@@ -65,7 +72,7 @@ def test_industry(self):
         """
         stock_data = PyTickerSymbols()
         self.assertIsNotNone(stock_data)
-        industries = stock_data.get_all_industries()
+        industries = list(stock_data.get_all_industries())
         self.assertIsNotNone(industries)
         self.assertIn("Computer Hardware", industries)
         self.assertIn("Gold", industries)
@@ -82,16 +89,16 @@ def test_stocks_by_index(self):
         """
         stock_data = PyTickerSymbols()
         self.assertIsNotNone(stock_data)
-        stocks = stock_data.get_stocks_by_index(None)
+        stocks = list(stock_data.get_stocks_by_index(None))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_index(False)
+        stocks = list(stock_data.get_stocks_by_index(False))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_index(True)
+        stocks = list(stock_data.get_stocks_by_index(True))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_index(22)
+        stocks = list(stock_data.get_stocks_by_index(22))
         self.assertEqual(len(stocks), 0)
         for ind, ctx in [('DAX',  30), ('CAC 40',  40)]:
-            stocks = stock_data.get_stocks_by_index(ind)
+            stocks = list(stock_data.get_stocks_by_index(ind))
             self.assertIsNotNone(stocks)
             self.assertEqual(len(stocks), ctx)
             for stock in stocks:
@@ -108,15 +115,15 @@ def test_stocks_by_country(self):
         """
         stock_data = PyTickerSymbols()
         self.assertIsNotNone(stock_data)
-        stocks = stock_data.get_stocks_by_country(None)
+        stocks = list(stock_data.get_stocks_by_country(None))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_country(False)
+        stocks = list(stock_data.get_stocks_by_country(False))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_country(True)
+        stocks = list(stock_data.get_stocks_by_country(True))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_country(22)
+        stocks = list(stock_data.get_stocks_by_country(22))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_country("Israel")
+        stocks = list(stock_data.get_stocks_by_country("Israel"))
         self.assertIsNotNone(stocks)
         self.assertTrue(len(stocks) >= 1)
         for stock in stocks:
@@ -132,15 +139,15 @@ def test_stocks_by_industry(self):
         """
         stock_data = PyTickerSymbols()
         self.assertIsNotNone(stock_data)
-        stocks = stock_data.get_stocks_by_industry(None)
+        stocks = list(stock_data.get_stocks_by_industry(None))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_industry(False)
+        stocks = list(stock_data.get_stocks_by_industry(False))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_industry(True)
+        stocks = list(stock_data.get_stocks_by_industry(True))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_industry(22)
+        stocks = list(stock_data.get_stocks_by_industry(22))
         self.assertEqual(len(stocks), 0)
-        stocks = stock_data.get_stocks_by_industry("Basic Materials")
+        stocks = list(stock_data.get_stocks_by_industry("Basic Materials"))
         self.assertIsNotNone(stocks)
         for stock in stocks:
             is_in_basic = False