#!/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 remainder(number, divisor): return number % divisor assert remainder(20, 7) == 6 # Example 2 remainder(20, 7) remainder(20, divisor=7) remainder(number=20, divisor=7) remainder(divisor=7, number=20) # Example 3 try: # This will not compile source = """remainder(number=20, 7)""" eval(source) except: logging.exception('Expected') else: assert False # Example 4 try: remainder(20, number=7) except: logging.exception('Expected') else: assert False # Example 5 my_kwargs = { 'number': 20, 'divisor': 7, } assert remainder(**my_kwargs) == 6 # Example 6 my_kwargs = { 'divisor': 7, } assert remainder(number=20, **my_kwargs) == 6 # Example 7 my_kwargs = { 'number': 20, } other_kwargs = { 'divisor': 7, } assert remainder(**my_kwargs, **other_kwargs) == 6 # Example 8 def print_parameters(**kwargs): for key, value in kwargs.items(): print(f'{key} = {value}') print_parameters(alpha=1.5, beta=9, gamma=4) # Example 9 def flow_rate(weight_diff, time_diff): return weight_diff / time_diff weight_diff = 0.5 time_diff = 3 flow = flow_rate(weight_diff, time_diff) print(f'{flow:.3} kg per second') # Example 10 def flow_rate(weight_diff, time_diff, period): return (weight_diff / time_diff) * period # Example 11 flow_per_second = flow_rate(weight_diff, time_diff, 1) # Example 12 def flow_rate(weight_diff, time_diff, period=1): return (weight_diff / time_diff) * period # Example 13 flow_per_second = flow_rate(weight_diff, time_diff) flow_per_hour = flow_rate(weight_diff, time_diff, period=3600) print(flow_per_second) print(flow_per_hour) # Example 14 def flow_rate(weight_diff, time_diff, period=1, units_per_kg=1): return ((weight_diff * units_per_kg) / time_diff) * period # Example 15 pounds_per_hour = flow_rate(weight_diff, time_diff, period=3600, units_per_kg=2.2) print(pounds_per_hour) # Example 16 pounds_per_hour = flow_rate(weight_diff, time_diff, 3600, 2.2) print(pounds_per_hour)