#!/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 gc import io import os 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 print('foo bar') # Example 2 my_value = 'foo bar' print(str(my_value)) print('%s' % my_value) print(f'{my_value}') print(format(my_value)) print(my_value.__format__('s')) print(my_value.__str__()) # Example 3 print(5) print('5') int_value = 5 str_value = '5' print(f'{int_value} == {str_value} ?') # Example 4 a = '\x07' print(repr(a)) # Example 5 b = eval(repr(a)) assert a == b # Example 6 print(repr(5)) print(repr('5')) # Example 7 print('%r' % 5) print('%r' % '5') int_value = 5 str_value = '5' print(f'{int_value!r} != {str_value!r}') # Example 8 class OpaqueClass: def __init__(self, x, y): self.x = x self.y = y obj = OpaqueClass(1, 'foo') print(obj) # Example 9 class BetterClass: def __init__(self, x, y): self.x = x self.y = y def __repr__(self): return f'BetterClass({self.x!r}, {self.y!r})' # Example 10 obj = BetterClass(2, 'bar') print(obj) # Example 11 obj = OpaqueClass(4, 'baz') print(obj.__dict__)