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@ProfAvery
Created February 9, 2012 05:39
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15 ways to sum an array in Ruby
#!/usr/bin/env ruby
require 'test/unit'
class TestSums < Test::Unit::TestCase
def setup
@a = [2, 5, 18, 27]
@sum = 0
end
def teardown
assert_equal 52, @sum
end
def test1
i = 0
while i < @a.length
@sum += @a[i]
i = i + 1
end
end
def test2
i = 0
begin
@sum += @a[i]
i = i + 1
end while i < @a.length
end
def test3
i = 0
until i >= @a.length
@sum += @a[i]
i = i + 1
end
end
def test4
i = 0
begin
@sum += @a[i]
i = i + 1
end until i >= @a.length
end
def test5
i = 0
loop do
@sum += @a[i]
i = i + 1
break if i >= @a.length
end
end
def test6
i = 0
@a.length.times {
@sum += @a[i]
i = i + 1
}
end
def test7
for i in 0 .. @a.length - 1
@sum += @a[i]
end
end
def test8
for i in @a
@sum += i
end
end
def test9
i = @a.to_enum
loop do
@sum += i.next
end
end
def test10
d = @a.dup
loop do
i = d.shift
break if i.nil?
@sum += i
end
end
def test11
0.upto(@a.length - 1){ |i| @sum += @a[i] }
end
def test12
@a.each { |i| @sum += i }
end
def test13
@a.each_index { |i| @sum += @a[i] }
end
def test14
@sum = @a.inject :+
end
def test15
@sum = eval @a.join '+'
end
end
@bhenry
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bhenry commented Feb 22, 2018

@sum = @a.reduce(&:+)

@sebastian-palma
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sebastian-palma commented Mar 5, 2018

@sum = @a.reduce(:+) # With base
@sum = @a.reduce(0, :+) # Without base
@sum = @a.sum # Ruby 2.4+

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