Cell Arrays

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• Misc
  • Colloquium
    • Brendan Murphy, U of R and Geneseo alumnus
    • Wednesday, April 27, 2:45 - 4:00, Newton 204
    • Extra credit as usual for write-ups
  • Final
    • Friday, May 6, 8:00 AM
    • In our classroom
    • Comprehensive, but emphasizing material since 2nd hour exam (e.g., vectorization, 3D arrays, images, cell arrays, strings, files, etc.)
    • Designed for 2 hours, you’ll have 2 1/2 +
    • Rules and format similar to hour exams
    • Donuts and cider
  • SOFIs
    • Helpful to me in planning future offerings of this course, especially comments on text
    • Please fill out
    • 1 filled out so far
• Questions?
• Cell Arrays
  • Sections 15.1 through 15.3
    • 15.1: definitions
      • Arrays can be char, number, logical, but elements must all have same class
      • String = characters between single quotes
      • Can make string arrays
    • 15.2: constructing cell arrays
      • Cell in array can hold string, number, etc.
      • Can hold different classes or sizes (useful)
    • 15.3: indexing cell arrays
      • Braces or parentheses for retrieving content...?
  • Visual model of cell arrays
    
  • Terminology of content indexing and cell indexing is more common that content and display indexing
  • Example: database of pets: name, species, age
    

    >> % Create a cell array
    >> pets = { 'Medea', 'cat', 16; 'Boris', 'cat', 3 }
    pets = 
        'Medea'    'cat'    [16]
        'Boris'    'cat'    [ 3]
    >> % Pick a specific value out of it
    >> pets{2,1}
    ans =
    Boris
    >> % Pick a cell out of it
    >> pets(2,1)
    ans = 
        'Boris'
    >> % Variations on cell and content indexing
    >> pets{2,1}(1)
    ans =
    B
    >> pets(1,:)
    ans = 
        'Medea'    'cat'    [16]
    >> pets{1,:}
    ans =
    Medea
    ans =
    cat
    ans =
        16
    >> [name,species,age] = pets{1,:}
    name =
    Medea
    species =
    cat
    age =
        16
    >> species
    species =
    cat
    >> % Add a new row to the cell array. Cell indexing because a row is a smaller cell array
    >> pets(3,:) = {'Molly', 'horse', 7}
    pets = 
        'Medea'    'cat'      [16]
        'Boris'    'cat'      [ 3]
        'Molly'    'horse'    [ 7]
    >> % Delete a row
    >> pets(3,:) = []
    pets = 
        'Medea'    'cat'    [16]
        'Boris'    'cat'    [ 3]
    >> % Change values
    >> pets{1,3} = 234
    pets = 
        'Medea'    'cat'    [234]
        'Boris'    'cat'    [  3]
    >> pets{1,3}= '16'
    pets = 
        'Medea'    'cat'    '16'
        'Boris'    'cat'    [ 3]
    >> % Swap rows
    >> pets([1,2],:) = pets([2,1],:)
    pets = 
        'Boris'    'cat'    [ 3]
        'Medea'    'cat'    '16'

• Next
  • Strings
  • Read sections 8.1 through 8.4

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