#!/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 def safe_division(number, divisor, ignore_overflow, ignore_zero_division): try: return number / divisor except OverflowError: if ignore_overflow: return 0 else: raise except ZeroDivisionError: if ignore_zero_division: return float('inf') else: raise # Example 2 result = safe_division(1.0, 10**500, True, False) print(result) # Example 3 result = safe_division(1.0, 0, False, True) print(result) # Example 4 def safe_division_b(number, divisor, ignore_overflow=False, # Changed ignore_zero_division=False): # Changed try: return number / divisor except OverflowError: if ignore_overflow: return 0 else: raise except ZeroDivisionError: if ignore_zero_division: return float('inf') else: raise # Example 5 result = safe_division_b(1.0, 10**500, ignore_overflow=True) print(result) result = safe_division_b(1.0, 0, ignore_zero_division=True) print(result) # Example 6 assert safe_division_b(1.0, 10**500, True, False) == 0 # Example 7 def safe_division_c(number, divisor, *, # Changed ignore_overflow=False, ignore_zero_division=False): try: return number / divisor except OverflowError: if ignore_overflow: return 0 else: raise except ZeroDivisionError: if ignore_zero_division: return float('inf') else: raise # Example 8 try: safe_division_c(1.0, 10**500, True, False) except: logging.exception('Expected') else: assert False # Example 9 result = safe_division_c(1.0, 0, ignore_zero_division=True) assert result == float('inf') try: result = safe_division_c(1.0, 0) except ZeroDivisionError: pass # Expected else: assert False # Example 10 assert safe_division_c(number=2, divisor=5) == 0.4 assert safe_division_c(divisor=5, number=2) == 0.4 assert safe_division_c(2, divisor=5) == 0.4 # Example 11 def safe_division_c(numerator, denominator, *, # Changed ignore_overflow=False, ignore_zero_division=False): try: return numerator / denominator except OverflowError: if ignore_overflow: return 0 else: raise except ZeroDivisionError: if ignore_zero_division: return float('inf') else: raise # Example 12 try: safe_division_c(number=2, divisor=5) except: logging.exception('Expected') else: assert False # Example 13 def safe_division_d(numerator, denominator, /, *, # Changed ignore_overflow=False, ignore_zero_division=False): try: return numerator / denominator except OverflowError: if ignore_overflow: return 0 else: raise except ZeroDivisionError: if ignore_zero_division: return float('inf') else: raise # Example 14 assert safe_division_d(2, 5) == 0.4 # Example 15 try: safe_division_d(numerator=2, denominator=5) except: logging.exception('Expected') else: assert False # Example 16 def safe_division_e(numerator, denominator, /, ndigits=10, *, # Changed ignore_overflow=False, ignore_zero_division=False): try: fraction = numerator / denominator # Changed return round(fraction, ndigits) # Changed except OverflowError: if ignore_overflow: return 0 else: raise except ZeroDivisionError: if ignore_zero_division: return float('inf') else: raise # Example 17 result = safe_division_e(22, 7) print(result) result = safe_division_e(22, 7, 5) print(result) result = safe_division_e(22, 7, ndigits=2) print(result)