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#!/usr/bin/env PYTHONHASHSEED=1234 python3
# Copyright 2014-2019 Brett Slatkin, Pearson Education Inc.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#     http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Reproduce book environment
import random
random.seed(1234)
import logging
from pprint import pprint
from sys import stdout as STDOUT
# Write all output to a temporary directory
import atexit
import tempfile
TEST_DIR = tempfile.TemporaryDirectory()
atexit.register(TEST_DIR.cleanup)
# Make sure Windows processes exit cleanly
OLD_CWD = os.getcwd()
atexit.register(lambda: os.chdir(OLD_CWD))
os.chdir(TEST_DIR.name)
def close_open_files():
    everything = gc.get_objects()
    for obj in everything:
        if isinstance(obj, io.IOBase):
            obj.close()
atexit.register(close_open_files)
# Example 1
class FrequencyList(list):
    def __init__(self, members):
        super().__init__(members)
    def frequency(self):
        counts = {}
        for item in self:
            counts[item] = counts.get(item, 0) + 1
        return counts
# Example 2
foo = FrequencyList(['a', 'b', 'a', 'c', 'b', 'a', 'd'])
print('Length is', len(foo))
print('After pop:', repr(foo))
print('Frequency:', foo.frequency())
# Example 3
class BinaryNode:
    def __init__(self, value, left=None, right=None):
        self.value = value
        self.left = left
        self.right = right
# Example 4
bar = [1, 2, 3]
# Example 5
bar.__getitem__(0)
# Example 6
class IndexableNode(BinaryNode):
    def _traverse(self):
        if self.left is not None:
            yield from self.left._traverse()
        yield self
        if self.right is not None:
            yield from self.right._traverse()
    def __getitem__(self, index):
        for i, item in enumerate(self._traverse()):
            if i == index:
                return item.value
        raise IndexError(f'Index {index} is out of range')
# Example 7
tree = IndexableNode(
    left=IndexableNode(
        left=IndexableNode(2),
        right=IndexableNode(
            right=IndexableNode(7))),
    right=IndexableNode(
        left=IndexableNode(11)))
# Example 8
print('LRR is', tree.left.right.right.value)
print('Index 0 is', tree[0])
print('Index 1 is', tree[1])
print('11 in the tree?', 11 in tree)
print('17 in the tree?', 17 in tree)
print('Tree is', list(tree))
    tree[100]
except IndexError:
    assert False
# Example 9
    len(tree)
    logging.exception('Expected')
    assert False
# Example 10
class SequenceNode(IndexableNode):
    def __len__(self):
        for count, _ in enumerate(self._traverse(), 1):
            pass
        return count
# Example 11
tree = SequenceNode(
    left=SequenceNode(
        left=SequenceNode(2),
        right=SequenceNode(
            right=SequenceNode(7))),
    right=SequenceNode(
        left=SequenceNode(11))
print('Tree length is', len(tree))
# Example 12
    # Make sure that this doesn't work
    tree.count(4)
    logging.exception('Expected')
    assert False
# Example 13
    from collections.abc import Sequence
    class BadType(Sequence):
        pass
    foo = BadType()
    logging.exception('Expected')
    assert False
# Example 14
class BetterNode(SequenceNode, Sequence):
tree = BetterNode(
    left=BetterNode(
        left=BetterNode(2),
        right=BetterNode(
            right=BetterNode(7))),
    right=BetterNode(
        left=BetterNode(11))
print('Index of 7 is', tree.index(7))
print('Count of 10 is', tree.count(10))
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