COSC 1306 - SET 4: Lists and Dictionaries

Assume price = 150 print('I saved $ --blank-- !' % price) Complete the code using formatting specifiers to generate the described output

%d

Assume percent = 40 print('Buy now! Save --blank-- !' % percent) Complete the code using formatting specifiers to generate the described output

%d%%

Assume item = 'backpack' and weight = 5.2 print('The %s is --blank-- pounds.' & (item, weight))

%f

Assume item = 'burrito' and price = 5 print('The -- blank-- is $%d' % (item, price))

%s

What is the value of sys.argv[1] given the following command-line input: python prog.py 'Tricia Miller' 26 (include quotes in your answer)

'Tricia Miller'

What is the value of sys.argv[1] given the following command-line input: python prog.py Tricia Miller 26 (include quotes in your answer)

'Tricia'

"I need 12 lilies, 6 roses, and 18 tulips." print(I need %(lilies)d lilies, %(roses)d roses, and %(tulips)d tulips.' % { ---blank---})

'lilies': 12, 'roses': 6, 'tulips': 18

"My name is Jerome and I'm 15 years old." print('My name is %(name)s and I am %(age)d years old' % { ---blank---})

'name': 'Jerome', 'age': 15

Count how many odd numbers (cnt_odd) there are. cnt_odd = __blank__ for i in num: if i % 2 == 1: cnt_odd += 1

0

my_list is [0, 5, 10, 15] What value is returned by min(my_list)?

0

nums = [[10, 20, 30], [98, 99]] What does nums[0][0] evaluate to?

10 nums[0] returns the list [10, 20, 30]. The 1st element of that list, nums[0][0], is 10.

nums = [10, 20, 30, 40, 50] for pos, value in enumerate(nums): tmp = value / 2 if (tmp % 2) == 0: nums[pos] = tmp What's the final value of nums[1]?

10.0

my_list is [0, 5, 10, 15] What value is returned by max(my_list)?

15

my_dict = dict(bananas=1.59, fries=2.39, burger=3.50, sandwich=2.99) my_dict['burger'] = my_dict['sandwich'] val = my_dict.pop('sandwich') print(my_dict['burger'])

2.99 removing a key only removes that key and any shared reference to a value still exists

scores = [ [75, 100, 82, 76], [85, 98, 89, 99], [75, 82, 85, 5] ] How many elements does scores contain? (The result of len(scores))

3

my_dict = dict(bananas=1.59, fries=2.39, burger=3.50, sandwich=2.99) my_dict.update(dict(soda=1.49, burger=3.69)) burger_price = my_dict.get('burger', 0) print(burger_price)

3.69

my_list is [0, 5, 10, 15] What value is returned by sum(my_list)?

30

What is the output of the following program? temps = [65, 67, 72, 75] temps.append(77) print(temps[-1])

77

nums = [[10, 20, 30], [98, 99]] What does nums[1][1] evaluate to?

99 nums[1] returns the list [98, 99]. The 2nd element of that list, nums[1][1], is 99.

The size of a list is determined when the list is created and cannot change.

False Lists can grow and shrink as necessary.

All elements of a list must have the same type.

False Lists can have heterogeneous types of elements.

The variable my_dict created with the following code contains two keys, 'Bob' and 'A+' my_dict = dict(name='Bob', grade='A+')

False The code creates a new dict containing the keys name and grade.

Dictionaries can contain, at most, three levels of nesting.

False The level of nesting is arbitrary.

my_list is [0, 5, 10, 15] What value is returned by all(my_list)?

False The list contains 0, thus all() returns False because not all elements are non-zero

nums = [0, 25, 50, 75, 100] The result of evaluating nums[0:5:2] is [25, 75]

False The start and end positions cover all the elements of the list. However, the stride is 2, so every other element, starting from 0 is extracted. Thus, the result is [0, 50, 100].

primes = [5, 13, 7] primes.sort() print(primes) The output of the following is [13, 7, 5]:

False list.sort() arranges the items from lowest to highest

The output of 'print(sorted([-5, 5, 2])) is [2, -5, 5]

False sorted() sorts elements of the given list argument and returns a new list, sorted from smallest to largest value

The statement 'del my_list[2]' produces a new list without the element in position 2.

False. 'del' performs in-place modification, returning the same list without deleted element.

What is the output of the following program? actors = ['Pitt', 'Damon'] actors.insert(1, 'Affleck') print(actors[0], actors[1], actors[2])

Pitt Affleck Damon Position 1 is the list initially is 'Damon'. The inserted value is placed at the position 1, and 'Damon' is moved to position 2.

A programmer can iterate over a copy of a list to safely make changes to that list.

True

Iterating over a list and deleting elements from the original list might cause a logic program error.

True

Nested dictionaries are a flexible way to organize data.

True

The sort() method modifies a list in-place

True

my_list is [0, 5, 10, 15] What value is returned by any(my_list)?

True

Dictionary entries can be modifies in-place - a new dictionary does not need to be created every times an element is added, changed, or removed.

True Dictionaries are mutable, just like lists

nums = [0, 25, 50, 75, 100] The result of evaluating nums[0:-1:3] is [0, 75]

True Every third element is extracted, starting at 0 and not including the last element of the list.

The statement my_list + my_list2 produces a new list.

True List concatenation appends the right operand to the left operand and creates a new list with the result.

A program can modify the elements of an existing list.

True Lists are mutable and elements can be added, removed, or changed as necessary.

The expression {'D1': {'D2': 'x'}} is valid

True The expression creates a nested dictionary with the key 'D1', containing the key D2 with the value 'x'.

Only negative odd values from the list x numbers = --blank-- Write a list comprehension that contains elements with the desired values. Use the name 'i' as the loop variable. Use parentheses around the expression or condition as necessary.

[(i) for i in x if ((i < 0) and (i % 2 == 1))]

my_list = [1, 1, 2, 3, 5, 8, 13, 21, 34] What is the result of my_list[len(my_list//2 : (len(my_list)//2 + 1)

[1, 1, 2, 3, 5, 8, 13, 21, 34]

nums = [1, 1, 2, 3, 5, 8, 13] What is the result of nums[1:5]?

[1, 2, 3, 5]

nums = [[10, 20, 30], [98, 99]] What does nums[0] evaluate to?

[10, 20, 30] nums[0] returns the list [10, 20, 30]

Whats the output of the list comprehension program in row 4 of the table above if my_list is [[5, 10], [1]]?

[15, 1]

my_list = [1, 1, 2, 3, 5, 8, 13, 21, 34] What is the result of my_list[2:5]

[2, 3, 5]

my_list = [1, 1, 2, 3, 5, 8, 13, 21, 34] What is the result of my_list[3:6]

[3, 5, 8]

nums = [1, 1, 2, 3, 5, 8, 13] What is the result of nums[3:-1]?

[3, 5, 8]

Whats the output of the list comprehension program from row 3 in the table above if the user enters "4 6 100"?

[4, 6, 100]

What's the output of the list comprehension program in row 1 in the table above if my_list is [-5, -4, -3]?

[5, 6, 7]

my_list = [1, 1, 2, 3, 5, 8, 13, 21, 34] What is the result of my_list[4:]

[5, 8, 13, 21, 34]

my_list = [1, 1, 2, 3, 5, 8, 13, 21, 34] What is the result of my_list[:20]

[5]

nums = [1, 1, 2, 3, 5, 8, 13] What is the result of nums[5: 10]?

[8, 13]

my_list = [1, 1, 2, 3, 5, 8, 13, 21, 34] What is the result of my_list[3:1]

[] empty set

The absolute value of each element in x. Use abs() function to find the absolute value of a number Write a list comprehension that contains elements with the desired values. Use the name 'i' as the loop variable.

[abs(i) for i in x]

Only negative values from the list x numbers = --blank-- Write a list comprehension that contains elements with the desired values. Use the name 'i' as the loop variable. Use parentheses around the expression or condition as necessary.

[i for i in x if i < 0]

Twice the value of each element in the list variable x Write a list comprehension that contains elements with the desired values. Use the name 'i' as the loop variable.

[i*2 for i in x]

animals = ['cat', 'dog', 'bird', 'raptor'] print(animals[0]) print(animals[2])

bird

animals = ['cat', 'dog', 'bird', 'raptor'] print(animals[0]) print(animals[0])

cat

Count how many negative numbers (cnt_neg) there are. cnt_neg = 0 for i in num: if i < 0: __blank__

cnt_neg += 1

Assume city = 'Boston' and distance = 2100 print('We are %d miles from %s.' % (---blank---))

distance, city

animals = ['cat', 'dog', 'bird', 'raptor'] print(animals[0]) print(animals[0 + 1]

dog 0 + 1 = 1

Alter the list comprehension from row 2 in the table above to convert each number to a float instead of a string. my_list = [5, 20, 50] my_list =[--blank-- for i in my_list] print(my_list)

float(i)

Determine the number of elements in the list that are divisible by 10. (Hint: the number x is divisible by 10 if x % 10 is 0.) div_ten = 0 for i in num: if __blank__: div_ten += 1

i % 10 == 0

The largest square root of any element in x. Use math.sqrt() to calculate the square root. Write a list comprehension that contains elements with the desired values. Use the name 'i' as the loop variable.

max([math.sqrt(i) for i in x])

Change all negative values in my_dict to 0. for key, values in --blank--: if value < 0: my_dict[key] = 0

my_dict.items()

Print each key in the dictionary my_dict for key in --blank--: print(key)

my_dict.keys() or my_dict

Print twice the value of every value in my_dict. for v in --blank--: print(2 * v)

my_dict.values()

Write a statement that counts the number of elements of my_list that have the value 15.

my_list.count(15)

Write the simplest two statements that first sort my_list, then remove the largest value element from the list, using list methods.

my_list.sort() my_list.pop() sort() arranges the elements from smallest to largest pop() removes the last element

Create a nested list nums whose only element is the list [21, 22, 23]

nums = [[21, 22, 23]]

animals = ['cat', 'dog', 'bird', 'raptor'] print(animals[0]) i = 3 print(animals[i])

raptor

scores = [ [75, 100, 82, 76], [85, 98, 89, 99], [75, 82, 85, 5] ] Write an indexing expression that gets the element from scores whose value is 100.

scores[0][1]

Alter the list comprehension from row 5 in the table above to calculate the sum of every number contained by my_list my_list = [[5, 10, 15], [2, 3, 16], [100]] sum_list = --blank--([sum(row) for row in my_list]) print(sum_list)

sum

Arrange the elements of z from lowest to highest, comparing the upper-case variant of each element in the list.

x.sort(key = str.upper)

Sort the elements of x such that the greatest element is in position 0.

x.sort(reverse = True)