FilesExpand file tree

 master

/

item_041.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

executable file

·

102 lines (82 loc) · 2.19 KB

 master

/

item_041.py

Copy path

Top

File metadata and controls

• Code
• Blame

executable file

·

102 lines (82 loc) · 2.19 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

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

#!/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")

matrix = [

[1, 2, 3],

[4, 5, 6],

[7, 8, 9],

]

flat = [x for row in matrix for x in row]

print(flat)

print("Example 2")

squared = [[x**2 for x in row] for row in matrix]

print(squared)

print("Example 3")

my_lists = [

[[1, 2, 3], [4, 5, 6]],

[[7, 8, 9], [10, 11, 12]],

]

flat = [x for sublist1 in my_lists

for sublist2 in sublist1

for x in sublist2]

print(flat)

print("Example 4")

flat = []

for sublist1 in my_lists:

for sublist2 in sublist1:

flat.extend(sublist2)

print(flat)

print("Example 5")

a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

b = [x for x in a if x > 4 if x % 2 == 0]

c = [x for x in a if x > 4 and x % 2 == 0]

print(b)

print(c)

assert b and c

assert b == c

print("Example 6")

matrix = [

[1, 2, 3],

[4, 5, 6],

[7, 8, 9],

]

filtered = [[x for x in row if x % 4 == 0]

for row in matrix if sum(row) >= 10]

print(filtered)