forked from bslatkin/effectivepython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathitem_032.py
More file actions
executable file
·125 lines (97 loc) · 2.71 KB
/
item_032.py
File metadata and controls
executable file
·125 lines (97 loc) · 2.71 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
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
#!/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")
def careful_divide(a, b):
try:
return a / b
except ZeroDivisionError:
return None
assert careful_divide(4, 2) == 2
assert careful_divide(0, 1) == 0
assert careful_divide(3, 6) == 0.5
assert careful_divide(1, 0) == None
print("Example 2")
x, y = 1, 0
result = careful_divide(x, y)
if result is None:
print("Invalid inputs")
else:
print(f"Result is {result:.1f}")
print("Example 3")
x, y = 0, 5
result = careful_divide(x, y)
if not result: # Changed
print("Invalid inputs") # This runs! But shouldn't
else:
assert False
print("Example 4")
def careful_divide(a, b):
try:
return True, a / b
except ZeroDivisionError:
return False, None
assert careful_divide(4, 2) == (True, 2)
assert careful_divide(0, 1) == (True, 0)
assert careful_divide(3, 6) == (True, 0.5)
assert careful_divide(1, 0) == (False, None)
print("Example 5")
x, y = 5, 0
success, result = careful_divide(x, y)
if not success:
print("Invalid inputs")
print("Example 6")
x, y = 5, 0
_, result = careful_divide(x, y)
if not result:
print("Invalid inputs")
print("Example 7")
def careful_divide(a, b):
try:
return a / b
except ZeroDivisionError:
raise ValueError("Invalid inputs") # Changed
print("Example 8")
x, y = 5, 2
try:
result = careful_divide(x, y)
except ValueError:
print("Invalid inputs")
else:
print(f"Result is {result:.1f}")