effectivepython/example_code/item_25.py at master · AISTLAB/effectivepython · GitHub

History

executable file

133 lines (99 loc) · 3.12 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

#!/usr/bin/env python3

# 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.

# Preamble to mimick book environment

import logging

from pprint import pprint

from sys import stdout as STDOUT

# Example 1

class MyBaseClass(object):

def __init__(self, value):

self.value = value

class MyChildClass(MyBaseClass):

def __init__(self):

MyBaseClass.__init__(self, 5)

def times_two(self):

return self.value * 2

foo = MyChildClass()

print(foo.times_two())

# Example 2

class TimesTwo(object):

def __init__(self):

self.value *= 2

class PlusFive(object):

def __init__(self):

self.value += 5

# Example 3

class OneWay(MyBaseClass, TimesTwo, PlusFive):

def __init__(self, value):

MyBaseClass.__init__(self, value)

TimesTwo.__init__(self)

PlusFive.__init__(self)

# Example 4

foo = OneWay(5)

print('First ordering is (5 * 2) + 5 =', foo.value)

# Example 5

class AnotherWay(MyBaseClass, PlusFive, TimesTwo):

def __init__(self, value):

MyBaseClass.__init__(self, value)

TimesTwo.__init__(self)

PlusFive.__init__(self)

# Example 6

bar = AnotherWay(5)

print('Second ordering still is', bar.value)

# Example 7

class TimesFive(MyBaseClass):

def __init__(self, value):

MyBaseClass.__init__(self, value)

self.value *= 5

class PlusTwo(MyBaseClass):

def __init__(self, value):

MyBaseClass.__init__(self, value)

self.value += 2

# Example 8

class ThisWay(TimesFive, PlusTwo):

def __init__(self, value):

TimesFive.__init__(self, value)

PlusTwo.__init__(self, value)

foo = ThisWay(5)

print('Should be (5 * 5) + 2 = 27 but is', foo.value)

# Example 11

# This is pretending to be Python 2 but it's not

class MyBaseClass(object):

def __init__(self, value):

self.value = value

class TimesFiveCorrect(MyBaseClass):

def __init__(self, value):

super(TimesFiveCorrect, self).__init__(value)

self.value *= 5

class PlusTwoCorrect(MyBaseClass):

def __init__(self, value):

super(PlusTwoCorrect, self).__init__(value)

self.value += 2

class GoodWay(TimesFiveCorrect, PlusTwoCorrect):

def __init__(self, value):

super(GoodWay, self).__init__(value)

before_pprint = pprint

pprint(GoodWay.mro())

from pprint import pprint

pprint(GoodWay.mro())

pprint = pprint

# Example 12

class Explicit(MyBaseClass):

def __init__(self, value):

super(__class__, self).__init__(value * 2)

class Implicit(MyBaseClass):

def __init__(self, value):

super().__init__(value * 2)

assert Explicit(10).value == Implicit(10).value

effectivepython/example_code/item_25.py at master · AISTLAB/effectivepython · GitHub

Expand file tree

Breadcrumbs

item_25.py

Latest commit

History

Breadcrumbs

item_25.py

File metadata and controls