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authormarcandre <marcandre@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2011-06-29 01:08:02 +0000
committermarcandre <marcandre@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2011-06-29 01:08:02 +0000
commitdfc6bf9da8a16b639a472f29ee72816d18263d6c (patch)
treeac45d698b65541b07dd5c3537dfa2583aaf43eee /lib/matrix.rb
parent87dadf3b8cd9b8bd2d5a5ba1a5009e289447f08a (diff)
* lib/matrix.rb: Matrix#each{_with_index} can iterate over a subset of the Matrix
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32277 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'lib/matrix.rb')
-rw-r--r--lib/matrix.rb129
1 files changed, 110 insertions, 19 deletions
diff --git a/lib/matrix.rb b/lib/matrix.rb
index 3fda08b..6c03706 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -365,36 +365,127 @@ class Matrix
#
# Yields all elements of the matrix, starting with those of the first row,
- # or returns an Enumerator is no block given
+ # or returns an Enumerator is no block given.
+ # Elements can be restricted by passing an argument:
+ # * :all (default): yields all elements
+ # * :diagonal: yields only elements on the diagonal
+ # * :off_diagonal: yields all elements except on the diagonal
+ # * :lower: yields only elements on or below the diagonal
+ # * :strict_lower: yields only elements below the diagonal
+ # * :strict_upper: yields only elements above the diagonal
+ # * :upper: yields only elements on or above the diagonal
+ #
# Matrix[ [1,2], [3,4] ].each { |e| puts e }
# # => prints the numbers 1 to 4
- #
- def each(&block) # :yield: e
- return to_enum(:each) unless block_given?
- @rows.each do |row|
- row.each(&block)
+ # Matrix[ [1,2], [3,4] ].each(:strict_lower).to_a # => [3]
+ #
+ def each(which = :all) # :yield: e
+ return to_enum :each, which unless block_given?
+ last = column_size - 1
+ case which
+ when :all
+ block = Proc.new
+ @rows.each do |row|
+ row.each(&block)
+ end
+ when :diagonal
+ @rows.each_with_index do |row, row_index|
+ yield row.fetch(row_index){return self}
+ end
+ when :off_diagonal
+ @rows.each_with_index do |row, row_index|
+ column_size.times do |col_index|
+ yield row[col_index] unless row_index == col_index
+ end
+ end
+ when :lower
+ @rows.each_with_index do |row, row_index|
+ 0.upto([row_index, last].min) do |col_index|
+ yield row[col_index]
+ end
+ end
+ when :strict_lower
+ @rows.each_with_index do |row, row_index|
+ [row_index, column_size].min.times do |col_index|
+ yield row[col_index]
+ end
+ end
+ when :strict_upper
+ @rows.each_with_index do |row, row_index|
+ (row_index+1).upto(last) do |col_index|
+ yield row[col_index]
+ end
+ end
+ when :upper
+ @rows.each_with_index do |row, row_index|
+ row_index.upto(last) do |col_index|
+ yield row[col_index]
+ end
+ end
+ else
+ Matrix.Raise ArgumentError, "expected #{which.inspect} to be one of :all, :diagonal, :off_diagonal, :lower, :strict_lower, :strict_upper or :upper"
end
self
end
#
- # Yields all elements of the matrix, starting with those of the first row,
- # along with the row index and column index,
- # or returns an Enumerator is no block given
+ # Same as #each, but the row index and column index in addition to the element
+ #
# Matrix[ [1,2], [3,4] ].each_with_index do |e, row, col|
# puts "#{e} at #{row}, #{col}"
# end
- # # => 1 at 0, 0
- # # => 2 at 0, 1
- # # => 3 at 1, 0
- # # => 4 at 1, 1
- #
- def each_with_index(&block) # :yield: e, row, column
- return to_enum(:each_with_index) unless block_given?
- @rows.each_with_index do |row, row_index|
- row.each_with_index do |e, col_index|
- yield e, row_index, col_index
+ # # => Prints:
+ # # 1 at 0, 0
+ # # 2 at 0, 1
+ # # 3 at 1, 0
+ # # 4 at 1, 1
+ #
+ def each_with_index(which = :all) # :yield: e, row, column
+ return to_enum :each_with_index, which unless block_given?
+ last = column_size - 1
+ case which
+ when :all
+ @rows.each_with_index do |row, row_index|
+ row.each_with_index do |e, col_index|
+ yield e, row_index, col_index
+ end
+ end
+ when :diagonal
+ @rows.each_with_index do |row, row_index|
+ yield row.fetch(row_index){return self}, row_index, row_index
+ end
+ when :off_diagonal
+ @rows.each_with_index do |row, row_index|
+ column_size.times do |col_index|
+ yield row[col_index], row_index, col_index unless row_index == col_index
+ end
+ end
+ when :lower
+ @rows.each_with_index do |row, row_index|
+ 0.upto([row_index, last].min) do |col_index|
+ yield row[col_index], row_index, col_index
+ end
end
+ when :strict_lower
+ @rows.each_with_index do |row, row_index|
+ [row_index, column_size].min.times do |col_index|
+ yield row[col_index], row_index, col_index
+ end
+ end
+ when :strict_upper
+ @rows.each_with_index do |row, row_index|
+ (row_index+1).upto(last) do |col_index|
+ yield row[col_index], row_index, col_index
+ end
+ end
+ when :upper
+ @rows.each_with_index do |row, row_index|
+ row_index.upto(last) do |col_index|
+ yield row[col_index], row_index, col_index
+ end
+ end
+ else
+ Matrix.Raise ArgumentError, "expected #{which.inspect} to be one of :all, :diagonal, :off_diagonal, :lower, :strict_lower, :strict_upper or :upper"
end
self
end