Here’s one way to do it. There are probably better ways.
rick@frodo:~/rubyscripts$ cat enum_contrast.rb
module Enumerable
def contrast(enum, eql_val=nil)
result = []
self.zip(enum) { |a, b| result << (a.eql?(b) ? eql_val :
b)}
result
end
def ordered_contrast(enum, eql_val=nil)
result = []
diff = false
self.zip(enum) do |a, b|
diff = diff || !a.eql?(b)
result << (diff ? b: eql_val)
end
result
end
def intersect(enum, diff_val=nil)
result = []
self.zip(enum) { |a, b| result << (a.eql?(b) ? b :
diff_val)}
result
end
def ordered_intersect(enum, diff_val=nil)
result = []
diff = false
self.zip(enum) do |a, b|
diff = diff || !a.eql?(b)
result << (diff ? diff_val : b)
end
result
end
end
class String
def to_chars_array
unpack('a'*length)
end
def contrast(str)
to_chars_array.contrast(str.to_chars_array,'
').join
end
def ordered_contrast(str)
to_chars_array.ordered_contrast(str.to_chars_array,’ ').join
end
def intersect(str)
to_chars_array.intersect(str.to_chars_array,'
').join
end
def ordered_intersect(str)
to_chars_array.ordered_intersect(str.to_chars_array,’ ').join
end
end
rick@frodo:~/rubyscripts$ cat test_enum_contrast.rb
require ‘enum_contrast.rb’
require ‘test/unit’
class TestSubranges < Test::Unit::TestCase
def test_array_contrast
assert_equal([ nil, nil, "c", nil ],
[ "a", "a", "b", "c" ].contrast([ "a",
“a”, “c”, “c” ]))
assert_equal([ nil, nil, "b", nil ],
[ "a", "a", "c", "c" ].contrast([ "a",
“a”, “b”, “c” ]))
assert_equal([ nil, nil, "c", nil ],
[ "a", "a", "b", "c" ].contrast([ "a",
“a”, “c”, “c” ]))
assert_equal([ "a", "a", nil, "c" ],
[ nil, nil, "c", nil ].contrast([ "a",
“a”, “c”, “c” ]))
end
def test_array_ordered_contrast
assert_equal([ nil, nil, "c","c" ],
[ "a", "a", "b", "c" ].ordered_contrast([
“a”, “a”, “c”, “c” ]))
assert_equal([ nil, nil, "b","c" ],
[ "a", "a", "c", "c" ].ordered_contrast([
“a”, “a”, “b”, “c” ]))
end
def test_array_intersect
assert_equal([ "a", "a", nil, "c" ],
[ "a", "a", "b", "c" ].intersect([ "a",
“a”, “c”, “c” ]))
end
def test_array_ordered_intersect
assert_equal([ "a", "a", nil, nil ],
[ "a", "a", "b", "c"
].ordered_intersect([ “a”, “a”, “c”, “c” ]))
end
def test_string_ordered_contrast
assert_equal(" cc",
"aabc".ordered_contrast( "aacc" ))
end
def test_string_contrast
assert_equal(" c ",
"aabc".contrast("aacc"))
end
def test_string_intersect
assert_equal("aa c",
"aabc".intersect("aacc"))
end
def test_string_ordered_intersect
assert_equal("aa ",
"aabc".ordered_intersect("aacc"))
end
end
rick@frodo:~/rubyscripts$ ruby test_enum_contrast.rb
Loaded suite test_enum_contrast
Started
…
Finished in 0.010052 seconds.
8 tests, 12 assertions, 0 failures, 0 errors
rick@frodo:~/rubyscripts$
Rick DeNatale
My blog on Ruby
http://talklikeaduck.denhaven2.com/