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Feature #2771
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Matrix: constructor to build with block
Description
=begin
I believe the following simple constructor could be a helpful addition to matrix.rb
class Matrix
Creates a matrix of +row_size+ x +column_size+.¶
It fills the values by calling the given block,¶
passing the current row and column.¶
m = Matrix.build(2, 4) {|row, col| col - row }¶
=> Matrix[[0, 1, 2, 3], [-1, 0, 1, 2]]¶
m = Matrix.build(3) { rand }¶
=> a 3x3 matrix with random elements¶
def self.build(row_size, column_size = row_size)
raise ArgumentError if row_size < 0 || column_size < 0
return to_enum :build, row_size, column_size unless block_given?
rows = row_size.times.map do |i|
column_size.times.map do |j|
yield i, j
end
end
new rows, column_size
end
end
=end
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