Are the following statements valid in Python 3?
a, b = 0 ** 3, 0 / 3
print(a, b)
a) Yes
b) No
The correct answer is a) Yes
The Python statement a, b = 0 ** 3, 0 / 3 is valid because it uses tuple unpacking to assign values. 0 ** 3 is 0 (since 0 to any power is 0), and 0 / 3 is also 0 (since 0 divided by any number is 0). Thus, a and b both get assigned the value 0.
In Python, which letter is used to represent imaginary numbers?
a) i
b) j
c) k
d) x
The correct answer is b) j
In Python, the letter j is used to represent the imaginary unit (traditionally denoted as i in mathematics) due to a convention in electrical engineering. In electrical engineering, i often represents current, so j is used instead to avoid confusion. This convention was adopted in Python for complex numbers.
In Python, 6 % 10 is 6. What's the output of following code snippet?
print (6 % -10)a) -6
b) -4
The correct answer is b) -4
In Python 3, the percentage symbol "%" is used as the modulo operator. a % b = a −(b * ⌊a / b⌋) Note, ⌊a / b⌋ is the floor division operation, which gives the largest integer less than or equal to the division result. ⌊6 / -10⌋ is −1 (since the largest integer less than −0.6 is −1). Plugging these into the equation: 6 −(−10 * −1) = 6 − 10 = −4
In Python, a set can contain duplicate items.
Please select 'True' if you think the statement is correct, or 'False' if it is incorrect.
a) True
b) False
The correct answer is b) False
In Python, a set is a collection type that is unordered and mutable. One of the key characteristics of a set is that it does not allow duplicate elements.
# Creating a set with duplicate items
my_set = {1, 2, 3, 2, 4, 1}
print(my_set) # Output will be {1, 2, 3, 4}Is there a way in Python to delete an element from a tuple?
a) Yes
b) No
The correct answer is b) No
Tuples in Python are immutable, which means you can't change their elements once they're created. However, you can work around this by converting the tuple to a list, removing the element, and then converting it back to a tuple.
What would be the result of evaluating the following Python code?
my_dict = {"a": 1, "b": 2}
x = my_dict.keys()
my_dict["c"] = 3
print(x)a) dict_keys(['a', 'b'])
b) ['a', 'b']
c) dict_keys(['a', 'b', 'c'])
d) ['a', 'b', 'c']
The correct answer is c) dict_keys(['a', 'b', 'c'])
In Python, when you call the .keys() method on a dictionary, it doesn't return a static list of keys. Instead, it returns a view object that displays the keys of the dictionary. This view object reflects any changes made to the dictionary.
Do you know which command correctly lists all installed Python packages?
a) pip list
b) pip --list
The correct answer is a) pip list
Note: pip list and pip freeze provide information about installed packages, pip list is more for human-readable output, and pip freeze is designed for generating machine-readable requirements files. ex.
root@localhost:~# pip list
Package Version
------------- -------
ephem 4.1.5
geographiclib 2.0
geopy 2.4.1
pip 23.3.2
pytz 2023.4
setuptools 69.0.3
wheel 0.42.0
root@localhost:~# pip freeze
ephem==4.1.5
geographiclib==2.0
geopy==2.4.1
pytz==2023.4
root@localhost:~# pip freeze > requirements.txt
root@localhost:~# cat requirements.txt
ephem==4.1.5
geographiclib==2.0
geopy==2.4.1
pytz==2023.4
pip list is more for human-readable output.
pip freeze is designed for generating machine-readable requirements files.
!pip list is a command that you would typically use in a Jupyter Notebook to list all installed Python packages.
What is the output of following Python code?
print([1, 2, 3] + [4, 5, 6])a) [5, 7, 9]
b) [1, 2, 3, 4, 5, 6]
The correct answer is b) [1, 2, 3, 4, 5, 6]
In Python, the + operator when used with lists performs list concatenation. This means it joins the two lists end-to-end. So, when you use [1, 2, 3] + [4, 5, 6], Python doesn't add the elements together numerically, but instead, it creates a new list that is the combination of the two lists.
Here's a breakdown of how it works:
You start with two lists: [1, 2, 3] and [4, 5, 6]. The + operator joins these lists, placing the elements of the second list directly after the elements of the first list. So, the output of print([1, 2, 3] + [4, 5, 6]) is indeed option b) [1, 2, 3, 4, 5, 6].
What's the output of this Python code?
a = True <= False
print(a)
a) 0
b) 1
c) False
d) True
The correct answer is c) False
In Python, the Boolean values True and False can also be understood as 1 and 0 respectively. So when you see True <= False, it's akin to evaluating 1 <= 0.
Now, let's evaluate the expression:
1 <= 0: This is asking, "Is 1 less than or equal to 0?" The answer is clearly no, because 1 is greater than 0. Therefore, this expression is False. When we assign this result to a, we get a = False.
So, when print(a) is executed, it prints False.
That's why the correct answer is C) False. It's a nifty example of how Python handles Boolean values and comparisons! 🐍✨
Which Python code correctly calculates and prints the sum of two numbers?
a) print(sum([5, 5]))
b) print(sum(5, 5))
The correct answer is a) print(sum([5, 5]))
Option a) print(sum([5, 5])): This is the correct way to use the sum() function in Python. sum() takes an iterable (like a list) as an argument. Here, [5, 5] is a list containing two elements, both 5. sum([5, 5]) correctly adds up these elements, resulting in 10, and print() then prints this result.
Option b) print(sum(5, 5)): This is incorrect because the sum() function does not accept individual numbers as separate arguments. It expects an iterable (like a list, tuple, etc.) as the first argument and optionally, a starting point as the second argument (which is not used here). Hence, this code will throw a TypeError.
What is the output of following Python code?
print(bool("False"))
a) True
b) False
c) 1
d) 0
The correct answer is a) True
This is because in Python, a non-empty string is considered "truthy," and when passed to the bool() function, it returns True. So, bool("False") results in True.
What is the output of following Python code?
print(1 + True)
a) 1
b) 2
c) TypeError!
d) 0
The correct answer is b) 2
In Python, True is treated as 1, so 1 + True equals 2.
Using the datetime module, which statement correctly prints the current date and time?
import datetime
a) print(datetime.date.now())
b) print(datetime.datetime.now())
The correct answer is b) print(datetime.datetime.now())
datetime.date.now(): This is not a valid method in the datetime module. date is a class that represents a date, without a time component. The now() method does not exist for the date class. If you want to get the current date, you would use datetime.date.today() instead.
datetime.datetime.now(): This is the correct way to get the current date and time. The datetime class in the datetime module represents both a date and a time. The now() method of this class returns the current local date and time. It includes year, month, day, hour, minute, second, and microsecond, which is what you typically need when you want the complete current date and time.
What is the output of following Python code?
mylist = [1, 2, 3, 4]
print(mylist[-1:-1])
a) []
b) 4
c) IndexError:
d) 1
The correct answer is a) []
mylist[-1:-1] results in an empty list as the start and stop indices are the same, including no elements.
What is the output of following Python code?
mydict = {"dob": 1998, "dob": 2002, "dob": 2005}
print(mydict["dob"])
a) 1998
b) 2002
c) 2005
d) KeyError:
The correct answer is c) 2005
In Python dictionaries, each key must be unique. If you assign multiple values to the same key, the last assignment overwrites the previous ones. In this example, the key dob is assigned three different values (1998, 2002, 2005), with 2005 being the last one. So, when we print mydict["dob"], it outputs 2005, the last assigned value.