Variables and Assignment Statements Quiz
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Questions and Answers

What does the left-hand side (LHS) of an assignment statement consist of?

  • A variable (correct)
  • An expression
  • A value
  • A comparison operator

    • Which data type is associated with a whole number without a fractional part?

  • Character
  • Integer (correct)
  • String
  • Float

    • What does the '=' sign do in an assignment statement?

  • Increments the variable by 1
  • Copies the value on the right side into the variable on the left side (correct)
  • Multiplies the two values
  • Compares two values

    • If an existing variable is assigned a new value, what happens?

    <p>The previous contents of the variable are cleared</p> Signup and view all the answers

    What happens when executing the assignment: 'cansPerPack = cansPerPack + 2'?

    <p>Adds 2 to cansPerPack</p> Signup and view all the answers

    What is not a data type mentioned in the text?

    <p>&quot;Alice&quot;</p> Signup and view all the answers

    Which of the following is NOT a valid variable name in Python?

    <p>2morrow</p> Signup and view all the answers

    In Python, what is the importance of using descriptive variable names?

    <p>It improves code readability and understanding</p> Signup and view all the answers

    What is the purpose of using named constants in Python?

    <p>To explain numerical values used in calculations</p> Signup and view all the answers

    Why is it customary to use all UPPER_CASE letters for constants in Python?

    <p>To make constants easier to identify in the code</p> Signup and view all the answers

    Which variable name is more self-descriptive?

    <p>canVolume = 0.35</p> Signup and view all the answers

    What can happen if a programmer does not use descriptive variable names in Python?

    <p>Other programmers will not be able to understand the code</p> Signup and view all the answers

    What is the correct syntax for naming variables in Python?

    <p>Variable names must start with a letter or underscore, and can contain letters, digits, and underscores</p> Signup and view all the answers

    Which of the following is an example of a floating-point number in Python?

    <p>0.5</p> Signup and view all the answers

    What is the term used for values like 6 or 0.355 that occur in a Python program?

    <p>Number literals</p> Signup and view all the answers

    Which of the following is NOT allowed when naming variables in Python?

    <p>Including spaces in variable names</p> Signup and view all the answers

    What will happen if a variable is assigned different data types at different points in a program in Python?

    <p>It will take the data type of the last assignment without issue</p> Signup and view all the answers

    Which statement correctly describes the naming of variables in Python?

    <p>'canVolume' is preferred over 'cv'</p> Signup and view all the answers

    Study Notes

    Variables and Data Types

    • A variable is defined and initialized using the assignment statement (=) and the data type is associated with the value, not the variable.
    • There are three types of data: whole numbers (integers), numbers with fractional parts (floats), and sequences of characters (strings).
    • Examples of integers: -7, 6, 24
    • Examples of floats: 8.88, -9.4, 1E6, 2.96E-2
    • Examples of strings: "Bob"

    Updating a Variable

    • If an existing variable is assigned a new value, the new value replaces the previous contents of the variable.
    • Example: cansPerPack = 6 then cansPerPack = 8 updates the value to 8.
    • Executing an assignment: cansPerPack = cansPerPack + 2 updates the value in two steps:
      • Calculate the right-hand side of the assignment.
      • Store the result in the variable on the left side.

    Number Types in Python

    • Integers: whole numbers without fractions, e.g. 6, -32
    • Floats: used when a fractional part is required, e.g. 0.5, 1.0, -9.4
    • Number literals: values that occur in a Python program, e.g. 6, 0.355

    Naming Variables

    • Variable names should describe the purpose of the variable, e.g. canVolume instead of cv.
    • Rules for naming variables:
      • Must start with a letter or underscore (_)
      • Can include letters, digits, or underscore, but no other symbols or spaces
      • Case sensitive, e.g. canVolume and canvolume are different
      • Should not use reserved Python words (see Appendix C)

    Constants

    • A constant is a variable whose value should not be changed after assignment.
    • Good practice to use all caps when naming constants, e.g. BOTTLE_VOLUME = 2.0.
    • Named constants can explain numerical values used in calculations, making code clearer.

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    Description

    Test your knowledge on variables, assignment statements, and expressions in programming. Learn about defining and initializing variables, using the assignment operator, and differentiating between the left-hand side and right-hand side of an assignment statement.

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