Updating for Python 3

Author: AllenDowney

code/Card.py

@@ -35,15 +35,14 @@ def __str__(self):
         return '%s of %s' % (Card.rank_names[self.rank],
                              Card.suit_names[self.suit])
 
-    def __cmp__(self, other):
+    def __lt__(self, other):
         """Compares this card to other, first by suit, then rank.
 
-        Returns a positive number if this > other; negative if other > this;
-        and 0 if they are equivalent.
+        returns: boolean
         """
         t1 = self.suit, self.rank
         t2 = other.suit, other.rank
-        return cmp(t1, t2)
+        return t1 < t2
 
 
 class Deck(object):

code/Markov.py

@@ -69,7 +69,7 @@ def random_text(self, n=100):
         n: number of words to generate
         """
         # choose a random prefix (not weighted by frequency)
-        start = random.choice(self.suffix_map.keys())
+        start = random.choice(list(self.suffix_map.keys()))
 
         for i in range(n):
             suffixes = self.suffix_map.get(start, None)

code/PokerHandSoln.py

@@ -51,7 +51,7 @@ def make_histograms(self):
             self.suits.count(c.suit)
             self.ranks.count(c.rank)
 
-        self.sets = self.ranks.values()
+        self.sets = list(self.ranks.values())
         self.sets.sort(reverse=True)
 
     def has_highcard(self):

code/Time1_soln.py

@@ -117,7 +117,7 @@ def main():
     race_time = Time()
     race_time.hour = 1
     race_time.minute = 34
-    race_time.second = 05
+    race_time.second = 5
 
     print('Half marathon time', end=' ')
     print_time(race_time)

code/anagram_sets.py

@@ -84,7 +84,7 @@ def filter_length(d, n):
     returns: new map from word to list of anagrams
     """
     res = {}
-    for word, anagrams in d.iteritems():
+    for word, anagrams in d.items():
         if len(word) == n:
             res[word] = anagrams
     return res

code/find_duplicates.py

@@ -114,7 +114,7 @@ def print_duplicates(d):
 
     d: map from checksum to list of files with that checksum
     """
-    for key, names in d.iteritems():
+    for key, names in d.items():
         if len(names) > 1:
             print('The following files have the same checksum:')
             for name in names:

code/find_duplicates_copy.py

@@ -114,7 +114,7 @@ def print_duplicates(d):
 
     d: map from checksum to list of files with that checksum
     """
-    for key, names in d.iteritems():
+    for key, names in d.items():
         if len(names) > 1:
             print('The following files have the same checksum:')
             for name in names:

code/invert_dict.py

@@ -23,14 +23,14 @@ def invert_dict(d):
     Returns: dict
     """
     inverse = {}
-    for key, val in d.iteritems():
+    for key, val in d.items():
         inverse.setdefault(val, []).append(key)
     return inverse
 
 
 if __name__ == '__main__':
     d = dict(a=1, b=2, c=3, z=1)
     inverse = invert_dict(d)
-    for val, keys in inverse.iteritems():
+    for val, keys in inverse.items():
         print(val, keys)
 

code/markov.py

@@ -77,7 +77,7 @@ def random_text(n=100):
     n: number of words to generate
     """
     # choose a random prefix (not weighted by frequency)
-    start = random.choice(suffix_map.keys())
+    start = random.choice(list(suffix_map.keys()))
 
     for i in range(n):
         suffixes = suffix_map.get(start, None)

code/most_frequent.py

@@ -22,7 +22,7 @@ def most_frequent(s):
     hist = make_histogram(s)
 
     t = []
-    for x, freq in hist.iteritems():
+    for x, freq in hist.items():
         t.append((freq, x))
 
     t.sort(reverse=True)

code/zipf.py

@@ -26,7 +26,7 @@ def rank_freq(hist):
     returns: list of (rank, freq) tuples
     """
     # sort the list of frequencies in decreasing order
-    freqs = hist.values()
+    freqs = list(hist.values())
     freqs.sort(reverse=True)
 
     # enumerate the ranks and frequencies