bites 81 - namedtuple sorting

Author: boraxpr

81/stay_positive.py

@@ -0,0 +1,40 @@
+from collections import namedtuple
+
+Tweet = namedtuple('Tweet', 'text polarity')
+
+# polarity < 0 = negative, > 0 = positive
+# long strings and pep8: you can wrap strings in () to reduce line length
+tweets = [
+    Tweet(text=("It's shocking that the vast majority of online banking "
+                "systems have critical vulnerabilities leaving customer "
+                "accounts unprotected."),
+          polarity=-0.3333333333333333),
+    Tweet(text=("The most unbelievable aspect of the Star Trek universe "
+                "is that every ship they meet has compatible video "
+                "conferencing facilities."),
+          polarity=0.125),
+    Tweet(text=("Excellent set of tips for managing a PostgreSQL cluster "
+                "in production."),
+          polarity=1.0),
+    Tweet(text=("This tutorial has a great line-by-line breakdown of how "
+                "to train a pong RL agent in PyTorch."),
+          polarity=0.8),
+    Tweet(text="This is some masterful reporting by ... It's also an "
+               "infuriating story. ... is trying to erase debt by preying "
+               "on the city’s residents. The poorest get hit the worst. "
+               "It’s shameful.",
+          polarity=-0.19999999999999998),
+]
+
+
+def filter_tweets_on_polarity(tweets, keep_positive=True):
+    """Filter the tweets by polarity score, receives keep_positive bool which
+       determines what to keep. Returns a list of filtered tweets."""
+    return list(filter(lambda x: (x.polarity > 0) == keep_positive, tweets))
+
+
+def order_tweets_by_polarity(tweets, positive_highest=True):
+    """Sort the tweets by polarity, receives positive_highest which determines
+       the order. Returns a list of ordered tweets."""
+    sorted_tweets_positive = sorted(tweets, key=lambda x: x.polarity, reverse=positive_highest)
+    return list(sorted_tweets_positive)

81/test_stay_positive.py

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+from stay_positive import (tweets, filter_tweets_on_polarity,
+                           order_tweets_by_polarity)
+
+
+def test_filter_tweets_keep_positive():
+    actual = filter_tweets_on_polarity(tweets)
+    expected = tweets[1:4]
+    assert actual == expected
+
+
+def test_filter_tweets_keep_negative():
+    actual = filter_tweets_on_polarity(tweets, keep_positive=False)
+    expected = [tweets[0], tweets[-1]]
+    assert actual == expected
+
+
+def test_order_tweets_positive_highest():
+    actual = [tweet.polarity for tweet in order_tweets_by_polarity(tweets)]
+    expected = [1.0, 0.8, 0.125, -0.19999999999999998,
+                -0.3333333333333333]
+    assert actual == expected
+
+
+def test_order_tweets_negative_highest():
+    actual = [tweet.polarity for tweet in
+              order_tweets_by_polarity(tweets, positive_highest=False)]
+    expected = [-0.3333333333333333, -0.19999999999999998,
+                0.125, 0.8, 1.0]
+    assert actual == expected