len() and sorted() Functions in Python Lists PCEP Exam preparation
PCEP Certification Practice Test - Questions, Answers and Explanations
Here are 25 questions based on the topic “functions: len(), sorted()” in Python collections (Tuples, Dictionaries, Lists, and Strings) designed for the PCEP-30-0x certification. The questions are in different formats like single-select, multiple-select, fill-in-the-gaps, sort, and code insertion.
Question 1: Which function is used to find the number of elements in a list?
- sorted()
- len()
- sum()
- range()
Answer: b) len()
Explanation: The len() function returns the number of items in a list or any other collection. The sorted() function is used to sort elements, not count them.
Question 2: What is the output of the following code?
fruits = ["apple", "banana", "cherry"] print(len(fruits))
- 1
- 2
- 3
- 4
Answer: c) 3
Explanation: The list fruits contains three items, so the len() function returns 3.
Question 3: Which of the following will sort the list [3, 1, 2] in ascending order?
- sorted([3, 1, 2])
- len([3, 1, 2])
- [3, 1, 2].sort()
- reverse([3, 1, 2])
Answer: a) sorted([3, 1, 2])
Explanation: The sorted() function returns a new list with the elements sorted. Option c) would work, but it modifies the list in place and does not return anything.
Question 4: Which of the following are correct uses of the len() function? (Choose two)
- len([1, 2, 3])
- len(5)
- len("hello")
- len((1, 2))
Answer: a) len([1, 2, 3]), c) len("hello")
Explanation: The len() function works with collections like lists, strings, and tuples. It does not work with single integers like in option b).
Question 5: Which of the following will return a sorted list in Python? (Choose all that apply)
- sorted(["b", "a", "c"])
- ["b", "a", "c"].sort()
- sorted([5, 3, 1])
- sorted({"z": 1, "y": 2, "x": 3})
Answer: a) sorted(["b", "a", "c"]), c) sorted([5, 3, 1]), d) sorted({"z": 1, "y": 2, "x": 3})
Explanation: Option b) modifies the list in place and does not return a new list. Option d) returns a list of the dictionary keys sorted in ascending order.
Question 6: Fill in the blank: The length of the list [10, 20, 30] is __________.
▼Answer: 3
Explanation: The list contains three elements, so len([10, 20, 30]) returns 3
Question 7: The code sorted(["delta", "alpha", "bravo"]) will return the list __________.
▼Answer: ['alpha', 'bravo', 'delta']
Explanation: The sorted() function arranges the strings in alphabetical order.
Question 8: Arrange the following code statements in the correct order to sort a list of numbers and print the length of the list:
- sorted_numbers = sorted(numbers)
- numbers = [7, 2, 5]
- print(len(sorted_numbers))
Answer: b) numbers = [7, 2, 5]
a) sorted_numbers = sorted(numbers)
c) print(len(sorted_numbers))
Explanation: The list needs to be defined first, followed by sorting it and finally printing its length.
Question 9: Arrange the following numbers in ascending order as they would appear after being sorted:
8, 3, 10, 2▼
Answer: 2, 3, 8, 10
Explanation: The numbers are arranged from smallest to largest when using the sorted() function.
Question 10: Complete the code to print the sorted version of the list animals:
animals = ["dog", "cat", "elephant"] print(__________)▼
Answer: sorted(animals)
Explanation: The sorted() function should be used to sort and print the list in alphabetical order.
Question 11: Complete the code to print the length of the tuple colors:
colors = ("red", "blue", "green") print(__________)")▼
Answer: len(colors)
Explanation: The len() function is used to determine the number of items in the tuple.
Question 12: Insert the correct code to sort the list of numbers [4, 2, 9, 1] and print the result.
numbers = [4, 2, 9, 1] __________▼
Answer: print(sorted(numbers))
Explanation: The code should use sorted(numbers) to sort the list and print() to display the sorted result.
Question 13: Insert the correct code to print the length of the string "Python".
word = "Python" __________▼
Answer: print(len(word))
Explanation: The len() function returns the number of characters in the string, which is then printed.
Question 14: Rearrange the items to sort the list ['zebra', 'ant', 'giraffe'] in alphabetical order and store it in sorted_animals:
- sorted_animals = sorted(animals)
- animals = ['zebra', 'ant', 'giraffe']
- print(sorted_animals)
Answer:
- animals = ['zebra', 'ant', 'giraffe']
- sorted_animals = sorted(animals)
- print(sorted_animals)
Explanation: First, the list is defined, then it’s sorted and stored, and finally, the result is printed.
Question 15: Organize the steps to determine the number of elements in the dictionary {1: "a", 2: "b", 3: "c"}:
- my_dict = {1: "a", 2: "b", 3: "c"}
- print(len(my_dict))
Answer: a) my_dict = {1: "a", 2: "b", 3: "c"}
b) print(len(my_dict))
Explanation: The dictionary is created first and then the length is printed using len().
Question 16: What does the following code output?
names = ["John", "Jane", "Doe"] print(len(sorted(names)))
- 3
- 2
- ["Doe", "Jane", "John"]
- None
Answer: a) 3
Explanation: The code sorts the list and then calculates the length, which remains 3 since the number of items doesn’t change.
Question 17: What does the following code output?
mixed_list = ["apple", 3, "banana", 1] print(sorted(mixed_list))
- ['apple', 'banana', 1, 3]
- Error
- [1, 3, 'apple', 'banana']
- None
Answer: b) Error
Explanation: The code results in an error because Python cannot directly compare strings with integers.
Question 18: The len() function can be used to determine the length of both tuples and strings.
- True
- False
Answer: a) True
Explanation: The len() function works with multiple collection types including strings, tuples, lists, and dictionaries.
Question 19: The sorted() function sorts a list in place without returning a new list.
- True
- False
Answer: b) False
Explanation: The sorted() function returns a new sorted list, leaving the original list unchanged.
Question 20: What will len([]) return?
- 0
- 1
- None
- Error
Answer: a) 0
Explanation: The length of an empty list is 0.
Question 21: What will be the result of sorted("Python")?
- ['Python']
- ['P', 'h', 'n', 'o', 't', 'y']
- ['P', 'y', 't', 'h', 'o', 'n']
- "Python"
Answer: b) ['P', 'h', 'n', 'o', 't', 'y']
Explanation: The sorted() function sorts the characters in the string according to their Unicode values, with uppercase letters appearing before lowercase letters.
Question 22: Which of the following operations are valid? (Choose two)
- sorted((5, 3, 1))
- len({"key1": "value1", "key2": "value2"})
- sorted(100)
- len(42)
Answer: a) sorted((5, 3, 1)), b) len({"key1": "value1", "key2": "value2"})
Explanation: sorted() works on tuples, and len() can determine the number of keys in a dictionary. The other options involve unsupported types for sorted() and len().
Question 23: The len() function can be used on any __________, while the sorted() function is used to sort collections.
▼Answer: collection
Explanation: The len() function is applicable to all collection types like lists, tuples, strings, and dictionaries.
Question 24: The function __________ is used to arrange items in a list in a specific order.
▼Answer: sorted()
Explanation: The sorted() function sorts the items either in ascending or descending order.
Question 25: What is the output of the following code?
words = ["pear", "apple", "banana"] print(len(sorted(words)))
- 1
- 2
- 3
- Error
Answer: c) 3
Explanation: The length of the sorted list remains the same as the original list because no items are removed or added.
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