FilesExpand file tree

 monkeyPatching

/

about_iteration.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

141 lines (100 loc) · 4.05 KB

 monkeyPatching

/

about_iteration.py

Copy path

Top

File metadata and controls

• Code
• Blame

141 lines (100 loc) · 4.05 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

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

134

135

136

137

138

139

140

141

#!/usr/bin/env python

# -*- coding: utf-8 -*-

from runner.koan import *

class AboutIteration(Koan):

def test_iterators_are_a_type(self):

it = iter(range(1,6))

fib = 0

for num in it:

fib += num

self.assertEqual(15 , fib)

def test_iterating_with_next(self):

stages = iter(['alpha','beta','gamma'])

try:

self.assertEqual('alpha', next(stages))

next(stages)

self.assertEqual('gamma', next(stages))

next(stages)

except StopIteration as ex:

err_msg = 'Ran out of iterations'

self.assertRegex(err_msg, r'Ran out')

# ------------------------------------------------------------------

def add_ten(self, item):

return item + 10

def test_map_transforms_elements_of_a_list(self):

seq = [1, 2, 3]

mapped_seq = list()

mapping = map(self.add_ten, seq)

self.assertNotEqual(list, mapping.__class__)

self.assertEqual(map, mapping.__class__)

# In Python 3 built in iterator funcs return iterable view objects

# instead of lists

for item in mapping:

mapped_seq.append(item)

self.assertEqual([11, 12, 13], mapped_seq)

# Note, iterator methods actually return objects of iter type in

# python 3. In python 2 map() would give you a list.

def test_filter_selects_certain_items_from_a_list(self):

def is_even(item):

return (item % 2) == 0

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

even_numbers = list()

for item in filter(is_even, seq):

even_numbers.append(item)

self.assertEqual([2, 4, 6], even_numbers)

def test_just_return_first_item_found(self):

def is_big_name(item):

return len(item) > 4

names = ["Jim", "Bill", "Clarence", "Doug", "Eli"]

name = None

iterator = filter(is_big_name, names)

try:

name = next(iterator)

except StopIteration:

msg = 'Ran out of big names'

self.assertEqual('Clarence', name)

# ------------------------------------------------------------------

def add(self,accum,item):

return accum + item

def multiply(self,accum,item):

return accum * item

def test_reduce_will_blow_your_mind(self):

import functools

# As of Python 3 reduce() has been demoted from a builtin function

# to the functools module.

result = functools.reduce(self.add, [2, 3, 4])

self.assertEqual(int, result.__class__)

# Reduce() syntax is same as Python 2

self.assertEqual(9, result)

result2 = functools.reduce(self.multiply, [2, 3, 4], 1)

self.assertEqual(24, result2)

# Extra Credit:

# Describe in your own words what reduce does.

# - it iteratively applies the provided function across

# the provided iterable of values, using the result

# as the following input, starting with the 3rd argument

# if one is provided

# ------------------------------------------------------------------

def test_use_pass_for_iterations_with_no_body(self):

for num in range(1,5):

pass

self.assertEqual(4, num)

# ------------------------------------------------------------------

def test_all_iteration_methods_work_on_any_sequence_not_just_lists(self):

# Ranges are an iterable sequence

result = map(self.add_ten, range(1,4))

self.assertEqual([11, 12, 13], list(result))

try:

file = open("example_file.txt")

try:

def make_upcase(line):

return line.strip().upper()

upcase_lines = map(make_upcase, file.readlines())

self.assertEqual(['THIS', 'IS', 'A', 'TEST'], list(upcase_lines))

finally:

# Arg, this is ugly.

# We will figure out how to fix this later.

file.close()

except IOError:

# should never happen

self.fail()