Lecture Notes: Using fprintf in MATLAB

Introduction

• Purpose: Inserting variable contents into text strings using fprintf.

Variable Definitions

• Variables Used:
  • numcats: 7
  • favcat: "floozy"

Using fprintf

• Objective: Construct a sentence using variables.
  • Sentence: "Of my 7 cats, floozy is my favorite."
• Syntax:
  • fprintf('Of my %g cats, %s is my favorite.\n', numcats, favcat);
  • %g: Used for inserting numbers (formats as integer here).
  • %s: Used for inserting text strings.
  • \n: New line character to end the sentence.

Working with Cell Arrays

• Cell Array Definition:
  • cats = {'floozy', 'cocoanut', 'upchuck', 'boom boom', 'doodle', 'Neptune', 'murky'};
• Sentence Construction:
  • Sentence Example: "My cat's name is Boom Boom."
  • Extraction Syntax: Use curly braces {} to extract text from a cell array.
  • Example: fprintf('My cat''s name is %s\n', cats{4});
  • Special Note: Use double single quotes '' for apostrophes.

Handling Multiple Elements in Cell Arrays

• Issue: Using fprintf on entire cell arrays without specifying elements causes errors.
• Error Handling:
  • Attempting to print entire array: fprintf('My cat''s name is %s\n', cats); results in error.
  • Solution: Extract all elements using curly braces and : operator.
  • Example to print all elements:

    fprintf('My cat''s name is %s\n', cats{1:length(cats)});
    

Understanding Output Recycling

• Recycling Concept: When more items are present than insertion points, MATLAB recycles the text string.
  • Example: "My cat's name is floozy." is followed by recycling for each subsequent element.
• Behavior: Prints each cat's name repeatedly using the same sentence structure.

Conclusion

• Next Steps: Understand the recycling of text strings better in contexts like creating tables with fprintf

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• Note: Always ensure proper extraction and formatting when working with arrays and fprintf. More details about table creation in the next lecture.