Python 3 Review Part 1

In the statement "my_number = 50", what is "my_number"?

• A function

• A variable name

• A constant

• A string

Answer explanation

In the statement "my_number = 50", "my_number" is a variable name that stores the value 50. It is not a function, constant, or string, making "A variable name" the correct choice.

Which of the following is NOT a float?

• 5.5

• 0.0

• 7

• 3.14

Answer explanation

A float is a number that has a decimal point. Among the options, 5.5, 0.0, and 3.14 are floats because they contain decimal points. The number 7 is an integer, thus it is NOT a float.

If `a = True` and `b = False`, what is the result of the expression `a and not b`?

• `True`

• `False`

• `None`

• `Error`

Answer explanation

In the expression `a and not b`, `a` is True and `not b` evaluates to True (since `b` is False). Therefore, `True and True` results in True. The correct answer is `True`.

What is the correct syntax to create a variable in Python?

• variable my_number = 50

• my_number = 50

• let my_number = 50

• const my_number = 50

Answer explanation

The correct syntax to create a variable in Python is 'my_number = 50'. This assigns the value 50 to the variable 'my_number'. The other options use syntax from different programming languages.

print("3"+"3")

• 33

• 6

• INVALID OUTPUT

Answer explanation

The expression print("3"+"3") concatenates two strings "3" and "3", resulting in "33". Therefore, the correct answer is 33.

How is a float different from an integer?

• It does not have a decimal component

• It is always positive

• It has a decimal component

• It is always negative

Answer explanation

A float differs from an integer in that it has a decimal component, allowing for fractional values. Integers are whole numbers without any decimal part.

Which of the following is a function call in the example?

• def print_a_number():

• x = 10

• print(x)

• print_a_number()

Answer explanation

The function call in the example is 'print_a_number()'. This line executes the function defined earlier, while 'def print_a_number():' defines the function, and 'print(x)' outputs the value of x but is not a function call.

Which of the following can a for loop do?

• repeat a task

• have a counter

• loop a certain amount of time

• All of these answers are correct.

Answer explanation

A for loop can repeat a task, have a counter to track iterations, and loop a specific number of times. Therefore, the correct answer is 'All of these answers are correct.'

Which of the following Python programs creates a list with the numbers 1 through 5?

• my_list = (1, 2, 3, 4, 5)

• my_list = [1, 2, 3, 4, 5]

• my_list = 1, 2, 3, 4, 5

• my_list = "1, 2, 3, 4, 5"

Answer explanation

The correct choice is 'my_list = [1, 2, 3, 4, 5]', which creates a list in Python. The other options either create a tuple, a sequence of values, or a string, none of which are lists.

What will be the output of the following code snippet? `print("Python"[1])`

• A) P

• B) y

• C) t

• D) h

Answer explanation

In Python, string indexing starts at 0. Therefore, `print("Python"[1])` accesses the second character, which is 'y'. Thus, the correct answer is B) y.