Files and Relations Lab

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• Misc
  • SOFIs
    • Helpful to me in teaching this (or other) courses in future
    • Access through myGeneseo/KnightWeb
  • Final
    • Dec. 22 (Tuesday), noon
    • Comprehensive, but emphasizing material since 2nd hour exam (e.g., cell arrays, strings, files)
    • Rules and format similar to hour exams, especially open references
    • Except designed for 2 hours, you have 3
    • Donuts and cider
• Questions?
• Files
  • Summary of section 6.5 in book
    • Save and load variables in binary
      • save( ’filename’ )
      • Save selected variables
        • save( ’filename’, ’var1’, ’var2’, … )
      • Or save filename, var1, var2, …
      • load( ’filename’ ) loads variables into workspace
    • Wizards to import data from other file formats
      • Recommended for import
  • Examples
    

    >> msg = 'hello there!';
    >> msg2 = 'more message';
    >> save( 'messages' );
    >> load( 'parrot.mat' );
    >> y
    y =
    Polly wants a cracker

• Relations Lab
  • Selection operation picks whole rows out of a cell array, based on whether those rows have a given value in a given column
  • e.g., selecting rows from mathContributions that have “Calculus” in column 2 would yield a new cell array containing copies of the first two rows of mathContributions
  • (But selection doesn’t exist as a Matlab function yet, you have to write it)
    

    >> mathContributions
    mathContributions = 
        'Isaac Newton'         'Calculus'               [1666]
        'Gottfried Leibniz'    'Calculus'               [1675]
        'Kurt Goedel'          'Incompleteness'         [1931]
        'Alan Turing'          'Computability'          [1936]
        'John von Neumann'     'von Neumann Algebra'    [1930]
    >> selection( mathContributions, 'Calculus', 2 )
    Undefined function or variable 'selection'.

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  • Relations lab day

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