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Exercise 0: Playing with chr and ord

Show the output that would be generated by the following program fragment:

msg = ""
for ch in "banana":
    mystery = chr(ord(ch) + 4)
    print(mystery)

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Exercise 1: Basic List operations

For this exercise, we’ll use the following statements:

numbers = [3, 1, 4, 1, 5]
words = ["apple", "banana", "cat", "dog", "elephant"]

Predict the result of evaluating each of the following list expressions.

a) numbers + words

b) 2 * numbers + words

c) numbers[-1]

d) words[1:4]

e) words[1] + words[2]

f) len(numbers)

g) for word in words:
       print(word[:3])

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Exercise 2: For-loop Patterns

Write a for loop using the variables numbers and words to generate each output. Think about whether you need the element and/or its index for each loop.

numbers = [3, 1, 4, 1, 5]
words = ["apple", "banana", "cat", "dog", "elephant"]

a) ae
   ba
   ct
   dg
   et

b) 0 apple
   1 banana
   2 cat
   3 dog
   4 elephant

c) 3
    1
     4
      1
       5

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Exercise 3: List Methods and Mutability

Predict the values of numbers and words after executing each of the following statements. Assume that numbers and words are reset to their original values before each statement.

numbers = [3, 1, 4, 1, 5]
words = ["apple", "banana", "cat", "dog", "elephant"]

a) numbers.remove(2)

b) numbers.sort()

c) words.sort(reverse=True)

d) numbers.append([words.index("cat")])

e) words.pop(numbers.pop(3))

f) words.insert(numbers[0], "fish")

Exercise 4: Going backwards

Exercise 4a: building a new result

Write a program to print a sequence of words in reverse order. You cannot use slicing or the existing reverse list method. (Hint: you should use split to turn the provided string into a list, and use the accumulator pattern to build the resulting list in reversed order.)

Here is an example interaction:

Please enter a sequence of words, separated by spaces: apple banana cat dog elephant fish

The sequence reversed:
fish elephant dog cat banana apple

Just for fun, see if you can build the resulting reversed list using a single slicing operation.

Exercise 4b: reversing in place

Now, instead of building up a new reversed result, reverse the provided list in-place, i.e. by modifying the original list, without using any additional variables. (Hint: remember that Python allows for simultaneous assignment.)

Here is an example interaction:

>>> mylist = ["apple", "banana", "cat"]
>>> mylist
['apple', 'banana', 'cat']
>>> YOUR CODE HERE
>>> mylist
['cat', 'banana', 'apple']

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