A Relational “Select” Algorithm

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• Misc
  • Colloquium
    • Wednesday, Dec. 3, 2:45 - 3:45 PM
    • Newton 201
    • “Learning with Leibniz”
    • Olympia Nicodemi
    • Extra credit
  • SOFIs
    • http://go.geneseo.edu/sofi_survey
  • Final Exam
    • Wednesday, Dec. 10, 8:00 AM
    • Comprehensive but emphasizing material since 2nd hour exam (e.g., cell arrays, files, strings)
    • Designed for 2 hours, you’ll have 3
    • Otherwise similar rules and format to hour exams, esp. open references and computers
    • Donuts and cider
• Questions?
• Relations Lab
  • Design “select” algorithm
    • What does it have to do? Give example(s)
      • Inputs: cell array, value for attribute, attribute index (column)
      • Value should be of whatever type is appropriate for that attribute
      • Search cell array for rows that have value in column
    • English description of how
      • Compare each value in column “column” to “value,” save rows with matches to new cell array
    • Pseudocode description
      

      function [newMatrix] = select( R, v, c )
          n = 1
          newMatrix = empty cell array
          for i = 1 : number of rows in R
              if R(i,c) == v        % cell or content index?
                  newMatrix(n,:) = R(i,:)
                  n = n + 1
              end
          end

  • Move “grade by” date for lesson 9 to Wednesday Dec. 10
• Next
  • Finish relations lab

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