#!/usr/bin/env PYTHONHASHSEED=1234 python3

# Copyright 2014-2024 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.

### Start book environment setup

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)

### End book environment setup

print("Example 1")

import math

import functools

def log_sum(log_total, value):

log_value = math.log(value)

return log_total + log_value

result = functools.reduce(log_sum, [10, 20, 40], 0)

print(math.exp(result))

print("Example 2")

def log_sum_alt(value, log_total): # Changed

log_value = math.log(value)

return log_total + log_value

print("Example 3")

result = functools.reduce(

lambda total, value: log_sum_alt(value, total), # Reordered

[10, 20, 40],

0,

)

print(math.exp(result))

print("Example 4")

def log_sum_for_reduce(total, value):

return log_sum_alt(value, total)

result = functools.reduce(

log_sum_for_reduce,

[10, 20, 40],

0,

)

print(math.exp(result))

print("Example 5")

def logn_sum(base, logn_total, value): # New first parameter

logn_value = math.log(value, base)

return logn_total + logn_value

print("Example 6")

result = functools.reduce(

lambda total, value: logn_sum(10, total, value), # Changed

[10, 20, 40],

0,

)

print(math.pow(10, result))

print("Example 7")

result = functools.reduce(

functools.partial(logn_sum, 10), # Changed

[10, 20, 40],

0,

)

print(math.pow(10, result))

print("Example 8")

def logn_sum_last(logn_total, value, *, base=10): # New last parameter

logn_value = math.log(value, base)

return logn_total + logn_value

print("Example 9")

import math

log_sum_e = functools.partial(logn_sum_last, base=math.e) # Pinned `base`

print(log_sum_e(3, math.e**10))

print("Example 10")

log_sum_e_alt = lambda *a, base=math.e, **kw: logn_sum_last(*a, base=base, **kw)

print(log_sum_e_alt(3, math.e**10))

print("Example 11")

print(log_sum_e.args, log_sum_e.keywords, log_sum_e.func)