1.7 Itse1359-1040-strings part 1

Table of contents

• Preface
  • Viewing tip
    • Figures
• Introduction to the string
  • Literals
    • An expression using variables
    • An expression using literals
    • String literals
    • A syntax error
    • A valid string literal
      • Proper syntax
      • Bad syntax
    • More examples
  • Triple-quoted strings
  • The newline (\n) character
    • Representing the newline character
    • An escape sequence
  • One more syntax option
• Escape sequences
  • The newline character
  • The built-in print function
    • Including the newline character
    • The print function renders according to meaning
  • The quote character
    • Escaping the quote character
    • Avoiding the quote problem
  • List of escape sequences
• More ways to span lines
  • End the line with a backslash
    • Not restricted to strings
    • A form of concatenation
  • Use the \n escape sequence
  • Combine backslash and \n
• String concatenation
  • Literal string concatenation
    • Concatenate through placement
    • Creating whitespace
    • Using + for concatenation
    • Whitespace is included in the quotes
  • Visualizing string concatenation
• More on strings later
• Miscellaneous

Preface

This module is one in a collection of modules on Python designed for teaching ITSE 1359 Introduction to Scripting Languages: Python at Austin Community College in Austin, TX. It provides an introduction to the use of stringsin Python.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view theFigures while you are reading about them.

(Note to blind and visually impaired students: most of the Figures in this module are presented in plaintext format and should be accessible using an audio screen reader or a braille display.)

Figures

• Figure 1 . String literals.
• Figure 2 . Triple-quoted strings.
• Figure 3 . Triple-quoted strings with newlines.
• Figure 4 . Using the newline character.
• Figure 5 . Escaping the quote character.
• Figure 6 . Avoiding the quote problem.
• Figure 7 . End the line with a backslash.
• Figure 8 . Use the \n escape sequence.
• Figure 9 . Combine backslash and \n.
• Figure 10 . Concatenate through placement.
• Figure 11 . Creating whitespace.
• Figure 12 . Visualizing string concatenation.

Introduction to the string

The common interpretation of the word string in computer programming is that a string is a sequence of characters that is treated as a unit. For example, a person's first and last names are often treated as two differentstrings.

A person's first name usually consists of several characters and these characters are treated as a unit to produce a name.

Literals

Perhaps the best way to describe a literal is to describe what it is not.

A literal is not a variable. In other words, the value of a literal doesn't change with time as the program executes. You might say that it is taken at facevalue.

An expression using variables

For example, the following expression describes the sum of two variables named var1 and var2 :

sum = var1 + var2

The result of this expression can vary depending on the values stored in var1 and var2 at the instant in time that the expression is evaluated.