strings
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(1) Characters

    + MATLAB's alphabet is essentially keyboard characters
      - see kb.gif and characters.txt from Lecture 3

    + reminders:

      - characters have integer value from 0 to 65355
      - our printable KB characters have values from char(33:126)
        (ASCII is 0 to 127)
      - use CHAR(int) to convert the integer to actual character rep
      - use DOUBLE(string) to convert the string to its integer value
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(2) Strings

    + MATLAB Strings
      - array of characters
      - in other languages, strings might be a different type of collection!!!

    + many useful functions
      see MATLAB's help: HELP STRINGS and HELP STRFUN

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(3) Empty String

    + Empty?
  
      ''  (two single quotes with nothing between)
      >> size('') % gives 0 rows and 0 cols

    Note: 

       >> $''==[]$ actually returns an error
       use ISEMPTY

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(4) Creating Strings

    + Creating 1D:
      - use CHAR (a bit tough) or single quotes ($'$)

        >> s = 'abc'

      - see also STRCAT
     
    + Creating 2D:
      - strings split into individual characters for rows/cols
  
        >> s = ['abc' ; 'def']  % OK

        >> s = ['abc' ; 'de']   % not OK

      - use CHAR to add padding and DEBLANK to remove padding
      - see also STRVCAT

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(5) String Operations

    + You can use arithmetic operators
      - why? strings are effectively arrays of ints in MATLAB
      - using ops forces strings to become ints again:

        >> 'abc' + 'def'
   
    + some specific values:

      double('a')   --> 97
      double('A')   --> 65

      >> 'a'-'A'    --> 32  
 
      >> 'Z'-'A'    --> 25
      >> 'z'-'a'    --> 25
     
      >> double('0123456789') -->  [48 49 50 51 52 53 54 56 57]

    + can use these values to help do things!

      >> char('b' - ('a'-'A') )

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(6) String Comparisons

    + use STRCMP to compare two strings
    + why?

      >> 'abc'=='abc'        % output is [1 1 1]

      >> strcmp('abc','abc') % output is 1

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(7) String Functions

    Taken directly from MATLAB!
    >> help strfun

    General.
      char        - Create character array (string).
      double      - Convert string to numeric character codes.
      cellstr     - Create cell array of strings from character array.
      blanks      - String of blanks.
      deblank     - Remove trailing blanks.
      eval        - Execute string with MATLAB expression.
 
    String tests.
      ischar      - True for character array (string).
      iscellstr   - True for cell array of strings.
      isletter    - True for letters of the alphabet.
      isspace     - True for white space characters.
 
    String operations.
      strcat      - Concatenate strings.
      strvcat     - Vertically concatenate strings.
      strcmp      - Compare strings.
      strncmp     - Compare first N characters of strings.
      strcmpi     - Compare strings ignoring case.
      strncmpi    - Compare first N characters of strings ignoring case.
      findstr     - Find one string within another.
      strjust     - Justify character array.
      strmatch    - Find possible matches for string.
      strrep      - Replace string with another.
      strtok      - Find token in string.
      upper       - Convert string to uppercase.
      lower       - Convert string to lowercase.
 
    String to number conversion.
      num2str     - Convert number to string.
      int2str     - Convert integer to string.
      mat2str     - Convert matrix to eval'able string.
      str2double  - Convert string to double precision value.
      str2num     - Convert string matrix to numeric array.
      sprintf     - Write formatted data to string.
      sscanf      - Read string under format control.
 
    Base number conversion.
      hex2num     - Convert IEEE hexadecimal to double precision number.
      hex2dec     - Convert hexadecimal string to decimal integer.
      dec2hex     - Convert decimal integer to hexadecimal string.
      bin2dec     - Convert binary string to decimal integer.
      dec2bin     - Convert decimal integer to binary string.
      base2dec    - Convert base B string to decimal integer.
      dec2base    - Convert decimal integer to base B string.

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