Lab 2: Nested Function Call Exercises

Do these exercises on the whiteboard with your partner(s).

Exercise Nested 1

def h(s):
    return '##' + s.lower()

def q(s):
    return s.upper() + '?'

Answer the following questions for the functions h and q defined above:

• Nested 1a:: What are the values of each of the following expressions?

  • h(q('d'))
  • q(h('e'))
  • h(q(h('F')))

• Nested 1b: Using h, q, and 'F', what is a different expression than h(q(h('F'))) that returns the same value?

• Nested 1c: Using h, q, and 'g', write three different expressions that evaluate to the string '##G???'

Exercise Nested 2

def z():
    """ zero """
    return 0

def d(n):
    """ double """
    return 2*n

def i(n):
    """ double and increment """
    return 2*n + 1

Answer the following questions for the functions z, d, and i defined above:

• Nested 2a: What are the values of each of the following expressions?

  • i(d(i(z())))
  • d(i(i(z())))

• Nested 2b: Using only calls to d, i, and z, write expressions that evaluate to the following integers:

  • 7
  • 10
  • 13
  • 15
  • 16

• Nested 2c: For any nonnegative integer n, is it possible to express n with an expression involving calls to only d, i, and z? Explain your answer.

• Nested 2d: For any integer n expressible involving calls to only d, i, and z, can there be more than one expression involving calls to only d, i, and z that evaluates to n?

Table of Contents

• Lab 2 Home
• Part 1: Function Call Exercises
• Part 2: Exercises from the Function Lecture Notebook
• Part 3: Debugging in Thonny