| blob | 0ce1d760558ae90d4967dfb89bee0ec7700f7a9a |
1 ##
2 # Enumerable
3 #
4 module Enumerable
5 ##
6 # call-seq:
7 # enum.drop(n) -> array
8 #
9 # Drops first n elements from <i>enum</i>, and returns rest elements
10 # in an array.
11 #
12 # a = [1, 2, 3, 4, 5, 0]
13 # a.drop(3) #=> [4, 5, 0]
15 def drop(n)
16 raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
17 raise ArgumentError, "attempt to drop negative size" if n < 0
19 ary = []
20 self.each {|*val| n == 0 ? ary << val.__svalue : n -= 1 }
21 ary
22 end
24 ##
25 # call-seq:
26 # enum.drop_while {|arr| block } -> array
27 #
28 # Drops elements up to, but not including, the first element for
29 # which the block returns +nil+ or +false+ and returns an array
30 # containing the remaining elements.
31 #
32 # a = [1, 2, 3, 4, 5, 0]
33 # a.drop_while {|i| i < 3 } #=> [3, 4, 5, 0]
35 def drop_while(&block)
36 ary, state = [], false
37 self.each do |*val|
38 state = true if !state and !block.call(*val)
39 ary << val.__svalue if state
40 end
41 ary
42 end
44 ##
45 # call-seq:
46 # enum.take(n) -> array
47 #
48 # Returns first n elements from <i>enum</i>.
49 #
50 # a = [1, 2, 3, 4, 5, 0]
51 # a.take(3) #=> [1, 2, 3]
53 def take(n)
54 raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
55 raise ArgumentError, "attempt to take negative size" if n < 0
57 ary = []
58 self.each do |*val|
59 break if ary.size >= n
60 ary << val.__svalue
61 end
62 ary
63 end
65 ##
66 # call-seq:
67 # enum.take_while {|arr| block } -> array
68 #
69 # Passes elements to the block until the block returns +nil+ or +false+,
70 # then stops iterating and returns an array of all prior elements.
71 #
72 #
73 # a = [1, 2, 3, 4, 5, 0]
74 # a.take_while {|i| i < 3 } #=> [1, 2]
76 def take_while(&block)
77 ary = []
78 self.each do |*val|
79 return ary unless block.call(*val)
80 ary << val.__svalue
81 end
82 ary
83 end
85 ##
86 # call-seq:
87 # enum.each_cons(n) {...} -> nil
88 #
89 # Iterates the given block for each array of consecutive <n>
90 # elements.
91 #
92 # e.g.:
93 # (1..10).each_cons(3) {|a| p a}
94 # # outputs below
95 # [1, 2, 3]
96 # [2, 3, 4]
97 # [3, 4, 5]
98 # [4, 5, 6]
99 # [5, 6, 7]
100 # [6, 7, 8]
101 # [7, 8, 9]
102 # [8, 9, 10]
104 def each_cons(n, &block)
105 raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
106 raise ArgumentError, "invalid size" if n <= 0
108 ary = []
109 self.each do |*val|
110 ary.shift if ary.size == n
111 ary << val.__svalue
112 block.call(ary.dup) if ary.size == n
113 end
114 end
116 ##
117 # call-seq:
118 # enum.each_slice(n) {...} -> nil
119 #
120 # Iterates the given block for each slice of <n> elements.
121 #
122 # e.g.:
123 # (1..10).each_slice(3) {|a| p a}
124 # # outputs below
125 # [1, 2, 3]
126 # [4, 5, 6]
127 # [7, 8, 9]
128 # [10]
130 def each_slice(n, &block)
131 raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
132 raise ArgumentError, "invalid slice size" if n <= 0
134 ary = []
135 self.each do |*val|
136 ary << val.__svalue
137 if ary.size == n
138 block.call(ary)
139 ary = []
140 end
141 end
142 block.call(ary) unless ary.empty?
143 end
145 ##
146 # call-seq:
147 # enum.group_by {| obj | block } -> a_hash
148 #
149 # Returns a hash, which keys are evaluated result from the
150 # block, and values are arrays of elements in <i>enum</i>
151 # corresponding to the key.
152 #
153 # (1..6).group_by {|i| i%3} #=> {0=>[3, 6], 1=>[1, 4], 2=>[2, 5]}
155 def group_by(&block)
156 h = {}
157 self.each do |*val|
158 key = block.call(*val)
159 sv = val.__svalue
160 h.key?(key) ? (h[key] << sv) : (h[key] = [sv])
161 end
162 h
163 end
165 ##
166 # call-seq:
167 # enum.sort_by { |obj| block } -> array
168 #
169 # Sorts <i>enum</i> using a set of keys generated by mapping the
170 # values in <i>enum</i> through the given block.
171 def sort_by(&block)
172 ary = []
173 orig = []
174 self.each_with_index{|e, i|
175 orig.push(e)
176 ary.push([block.call(e), i])
177 }
178 if ary.size > 1
179 __sort_sub__(ary, ::Array.new(ary.size), 0, 0, ary.size - 1) do |a,b|
180 a <=> b
181 end
182 end
183 ary.collect{|e,i| orig[i]}
184 end
186 NONE = Object.new
187 ##
188 # call-seq:
189 # enum.first -> obj or nil
190 # enum.first(n) -> an_array
191 #
192 # Returns the first element, or the first +n+ elements, of the enumerable.
193 # If the enumerable is empty, the first form returns <code>nil</code>, and the
194 # second form returns an empty array.
195 def first(n=NONE)
196 if n == NONE
197 self.each do |*val|
198 return val.__svalue
199 end
200 return nil
201 else
202 a = []
203 i = 0
204 self.each do |*val|
205 break if n<=i
206 a.push val.__svalue
207 i += 1
208 end
209 a
210 end
211 end
213 ##
214 # call-seq:
215 # enum.count -> int
216 # enum.count(item) -> int
217 # enum.count { |obj| block } -> int
218 #
219 # Returns the number of items in +enum+ through enumeration.
220 # If an argument is given, the number of items in +enum+ that
221 # are equal to +item+ are counted. If a block is given, it
222 # counts the number of elements yielding a true value.
223 def count(v=NONE, &block)
224 count = 0
225 if block
226 self.each do |*val|
227 count += 1 if block.call(*val)
228 end
229 else
230 if v == NONE
231 self.each { count += 1 }