E77: INTRODUCTION TO COMPUTER PROGRAMMING FOR SCIENTISTS AND ENGINEERS

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E77 INTRODUCTION TO COMPUTER PROGRAMMING FOR
SCIENTISTS AND ENGINEERS

• Lecture Outline
• 1. Introduction to arrays
• 2. One-dimensional arrays
• 3. Character strings

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Introduction to arrays

• 1. Introduction to arrays
• A simple array is an ordered collection of real
  numbers.
• MATLAB treats arrays as a particular data type
  and
• handles them very efficiently, in terms of
• Input/output, indexing and addressing
• Arithmetic operations
• Other manipulations (e.g., sizing, reshaping,
  etc.)
• Arrays are the primary building blocks in MATLAB.

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Introduction to arrays

• Examples
• 
  (1 row, 1 column)
• 
  (1 row,4 columns)
• 
  (3 rows, 1 column)
• 
  (2 rows, 3 columns)

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One-dimensional arrays

• 2. One-dimensional arrays
• Consider first one-dimensional simple arrays,
  i.e., those
• that have one row and/or one column.
• Construction (manual, incremental, linspace,
• zeros,ones,rand,randperm)
• Addressing (), sizing (length)
• Manipulation (transposition, concatenation,
  row/column addition)
• Arithmetic operations (scalar addition/multiplicat
  ion,
• array addition/multiplication, array
  exponentiation)

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One-dimensional arrays

• Example
• Convert a one-dimensional array containing
  temperatures
• in the Farenheit scale to temperatures in the
  Celcius scale.
• What is the conversion rule?

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One-dimensional arrays

• Example
• Convert a one-dimensional array containing
  temperatures
• in the Farenheit scale to temperatures in the
  Celcius scale.
• What is the conversion rule?

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Character strings

• 3. Character strings
• In addition to numbers, many computer programs
  also
• need to deal with text data, e.g.,
• Names and addresses
• Input and output prompts
• Labels
• Text files
• Character strings in MATLAB are special arrays
  displayed
• in text format, but stored and manipulated in
  numerical
• format.

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Character strings

• How are strings implemented in MATLAB?
• Construction (' ')
• Conversion to numbers (double) and vice-versa
  (char)
• MATLAB recognizes 256 characters
• Addressing, sizing and searching (findstr)
• Manipulation (transposition, reversal,
  concatenation,
• upper-/lowercase conversion)
• String arrays

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One-dimensional arrays

• Example
• Manipulate the roster of E77
• Name matching (strmatch)
• Reverse the alphabetical order of the classlist
• Order classlist randomly
• Can everyone make an A in this class?

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Summary

• What did we learn today?
• Arrays are important data structures and can be
• treated with great efciency in MATLAB.
• Many different MATLAB built-in functions can be
• employed to input, manipulate and output arrays.
• Strings are numerical arrays in disguise and are
• employed to treat text data.
• Many different MATLAB built-in functions can be
• employed to input, manipulate and output strings
  and
• string arrays.