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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
module Enumerable
# Enumerable#sum was added in Ruby 2.4, but it only works with Numeric elements
# when we omit an identity.
#
# We tried shimming it to attempt the fast native method, rescue TypeError,
# and fall back to the compatible implementation, but that's much slower than
# just calling the compat method in the first place.
if Enumerable.instance_methods(false).include?(:sum) && !((?a..?b).sum rescue false)
# We can't use Refinements here because Refinements with Module which will be prepended
# doesn't work well https://bugs.ruby-lang.org/issues/13446
alias :_original_sum_with_required_identity :sum
private :_original_sum_with_required_identity
# Calculates a sum from the elements.
#
# payments.sum { |p| p.price * p.tax_rate }
# payments.sum(&:price)
#
# The latter is a shortcut for:
#
# payments.inject(0) { |sum, p| sum + p.price }
#
# It can also calculate the sum without the use of a block.
#
# [5, 15, 10].sum # => 30
# ['foo', 'bar'].sum # => "foobar"
# [[1, 2], [3, 1, 5]].sum # => [1, 2, 3, 1, 5]
#
# The default sum of an empty list is zero. You can override this default:
#
# [].sum(Payment.new(0)) { |i| i.amount } # => Payment.new(0)
def sum(identity = nil, &block)
if identity
_original_sum_with_required_identity(identity, &block)
elsif block_given?
map(&block).sum(identity)
else
inject(:+) || 0
end
end
else
def sum(identity = nil, &block)
if block_given?
map(&block).sum(identity)
else
sum = identity ? inject(identity, :+) : inject(:+)
sum || identity || 0
end
end
end
# Convert an enumerable to a hash.
#
# people.index_by(&:login)
# # => { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...}
# people.index_by { |person| "#{person.first_name} #{person.last_name}" }
# # => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
def index_by
if block_given?
result = {}
each { |elem| result[yield(elem)] = elem }
result
else
to_enum(:index_by) { size if respond_to?(:size) }
end
end
# Returns +true+ if the enumerable has more than 1 element. Functionally
# equivalent to <tt>enum.to_a.size > 1</tt>. Can be called with a block too,
# much like any?, so <tt>people.many? { |p| p.age > 26 }</tt> returns +true+
# if more than one person is over 26.
def many?
cnt = 0
if block_given?
any? do |element|
cnt += 1 if yield element
cnt > 1
end
else
any? { (cnt += 1) > 1 }
end
end
# The negative of the <tt>Enumerable#include?</tt>. Returns +true+ if the
# collection does not include the object.
def exclude?(object)
!include?(object)
end
# Returns a copy of the enumerable without the specified elements.
#
# ["David", "Rafael", "Aaron", "Todd"].without "Aaron", "Todd"
# # => ["David", "Rafael"]
#
# {foo: 1, bar: 2, baz: 3}.without :bar
# # => {foo: 1, baz: 3}
def without(*elements)
reject { |element| elements.include?(element) }
end
# Convert an enumerable to an array based on the given key.
#
# [{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pluck(:name)
# # => ["David", "Rafael", "Aaron"]
#
# [{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pluck(:id, :name)
# # => [[1, "David"], [2, "Rafael"]]
def pluck(*keys)
if keys.many?
map { |element| keys.map { |key| element[key] } }
else
map { |element| element[keys.first] }
end
end
end
class Range #:nodoc:
# Optimize range sum to use arithmetic progression if a block is not given and
# we have a range of numeric values.
def sum(identity = nil)
if block_given? || !(first.is_a?(Integer) && last.is_a?(Integer))
super
else
actual_last = exclude_end? ? (last - 1) : last
if actual_last >= first
sum = identity || 0
sum + (actual_last - first + 1) * (actual_last + first) / 2
else
identity || 0
end
end
end
end
# Array#sum was added in Ruby 2.4 but it only works with Numeric elements.
#
# We tried shimming it to attempt the fast native method, rescue TypeError,
# and fall back to the compatible implementation, but that's much slower than
# just calling the compat method in the first place.
if Array.instance_methods(false).include?(:sum) && !(%w[a].sum rescue false)
# Using Refinements here in order not to expose our internal method
using Module.new {
refine Array do
alias :orig_sum :sum
end
}
class Array
def sum(init = nil, &block) #:nodoc:
if init.is_a?(Numeric) || first.is_a?(Numeric)
init ||= 0
orig_sum(init, &block)
else
super
end
end
end
end
|
