[2023年10月]更新のPython Institute PCEP-30-02試験練習テスト問題 [Q14-Q31]

[2023年10月]更新のPython Institute PCEP-30-02試験練習テスト問題

更新された認定試験PCEP-30-02問題集で練習テスト問題

質問 # 14
Assuming that the following assignment has been successfully executed:
My_list - [1, 1, 2, 3]
Select the expressions which will not raise any exception.
(Select two expressions.)

A. my_list|my_Li1st | 3| I
B. my list [6]
C. my_list[-10]
D. my_List- [0:1]

正解：A、D

解説：
Explanation
The code snippet that you have sent is assigning a list of four numbers to a variable called "my_list". The code is as follows:
my_list = [1, 1, 2, 3]
The code creates a list object that contains the elements 1, 1, 2, and 3, and assigns it to the variable "my_list".
The list can be accessed by using the variable name or by using the index of the elements. The index starts from 0 for the first element and goes up to the length of the list minus one for the last element. The index can also be negative, in which case it counts from the end of the list. For example, my_list[0] returns 1, and my_list[-1] returns 3.
The code also allows some operations on the list, such as slicing, concatenation, repetition, and membership.
Slicing is used to get a sublist of the original list by specifying the start and end index. For example, my_list[1:3] returns [1, 2]. Concatenation is used to join two lists together by using the + operator. For example, my_list + [4, 5] returns [1, 1, 2, 3, 4, 5]. Repetition is used to create a new list by repeating the original list a number of times by using the * operator. For example, my_list * 2 returns [1, 1, 2, 3, 1, 1, 2, 3].
Membership is used to check if an element is present in the list by using the in operator. For example, 2 in my_list returns True, and 4 in my_list returns False.
The expressions that you have given are trying to access or manipulate the list in different ways. Some of them are valid, and some of them are invalid and will raise an exception. An exception is an error that occurs when the code cannot be executed properly. The expressions are as follows:
A). my_list[-10]: This expression is trying to access the element at the index -10 of the list. However, the list only has four elements, so the index -10 is out of range. This will raise an IndexError exception and output nothing.
B). my_list|my_Li1st | 3| I: This expression is trying to perform a bitwise OR operation on the list and some other operands. The bitwise OR operation is used to compare the binary representation of two numbers and return a new number that has a 1 in each bit position where either number has a 1. For example, 3 | 1 returns 3, because 3 in binary is 11 and 1 in binary is 01, and 11 | 01 is 11. However, the bitwise OR operation cannot be applied to a list, because a list is not a number. This will raise a TypeError exception and output nothing.
C). my list [6]: This expression is trying to access the element at the index 6 of the list. However, the list only has four elements, so the index 6 is out of range. This will raise an IndexError exception and output nothing.
D). my_List- [0:1]: This expression is trying to perform a subtraction operation on the list and a sublist. The subtraction operation is used to subtract one number from another and return the difference. For example, 3 - 1 returns 2. However, the subtraction operation cannot be applied to a list, because a list is not a number. This will raise a TypeError exception and output nothing.
Only two expressions will not raise any exception. They are:
B). my_list|my_Li1st | 3| I: This expression is not a valid Python code, but it is not an expression that tries to access or manipulate the list. It is just a string of characters that has no meaning. Therefore, it will not raise any exception, but it will also not output anything.
D). my_List- [0:1]: This expression is a valid Python code that uses the slicing operation to get a sublist of the list. The slicing operation does not raise any exception, even if the start or end index is out of range. It will just return an empty list or the closest possible sublist. For example, my_list[0:10] returns [1, 1, 2, 3], and my_list[10:20] returns []. The expression my_List- [0:1] returns the sublist of the list from the index 0 to the index 1, excluding the end index. Therefore, it returns [1]. This expression will not raise any exception, and it will output [1].
Therefore, the correct answers are B. my_list|my_Li1st | 3| I and D. my_List- [0:1].

質問 # 15
What is the expected result of the following code?

A. 0
B. The code will cause an unhandled
C. 1
D. 2

正解：B

解説：
Explanation
The code snippet that you have sent is trying to use a list comprehension to create a new list from an existing list. The code is as follows:
my_list = [1, 2, 3, 4, 5] new_list = [x for x in my_list if x > 5]
The code starts with creating a list called "my_list" that contains the numbers 1, 2, 3, 4, and 5. Then, it tries to create a new list called "new_list" by using a list comprehension. A list comprehension is a concise way of creating a new list from an existing list by applying some expression or condition to each element. The syntax of a list comprehension is:
new_list = [expression for element in old_list if condition]
The expression is the value that will be added to the new list, which can be the same as the element or a modified version of it. The element is the variable that takes each value from the old list. The condition is an optional filter that determines which elements will be included in the new list. For example, the following list comprehension creates a new list that contains the squares of the even numbers from the old list:
old_list = [1, 2, 3, 4, 5, 6] new_list = [x ** 2 for x in old_list if x % 2 == 0] new_list = [4, 16, 36]The code that you have sent is trying to create a new list that contains the elements from the old list that are greater than 5. However, there is a problem with this code. The problem is that none of the elements in the old list are greater than 5, so the condition is always false. This means that the new list will be empty, and the expression will never be evaluated. However, the expression is not valid, because it uses the variable x without defining it. This will cause a NameError exception, which is an error that occurs when a variable name is not found in the current scope. The code does not handle the exception, and therefore it will terminate with an error message.
The expected result of the code is an unhandled exception, because the code tries to use an undefined variable in an expression that is never executed. Therefore, the correct answer is D. The code will cause an unhandled exception.

質問 # 16
What is true about exceptions and debugging? (Select two answers.)

A. The default (anonymous) except branch cannot be the last branch in the try-except block.
B. A tool that allows you to precisely trace program execution is called a debugger.
C. One try-except block may contain more than one except branch.
D. If some Python code is executed without errors, this proves that there are no errors in it.

正解：B、C

解説：
Explanation
Exceptions and debugging are two important concepts in Python programming that are related to handling and preventing errors. Exceptions are errors that occur when the code cannot be executed properly, such as syntax errors, type errors, index errors, etc. Debugging is the process of finding and fixing errors in the code, using various tools and techniques. Some of the facts about exceptions and debugging are:
A tool that allows you to precisely trace program execution is called a debugger. A debugger is a program that can run another program step by step, inspect the values of variables, set breakpoints, evaluate expressions, etc. A debugger can help you find the source and cause of an error, and test possible solutions. Python has a built-in debugger module called pdb, which can be used from the command line or within the code. There are also other third-party debuggers available for Python, such as PyCharm, Visual Studio Code, etc12 If some Python code is executed without errors, this does not prove that there are no errors in it. It only means that the code did not encounter any exceptions that would stop the execution. However, the code may still have logical errors, which are errors that cause the code to produce incorrect or unexpected results. For example, if you write a function that is supposed to calculate the area of a circle, but you use the wrong formula, the code may run without errors, but it will give you the wrong answer. Logical errors are harder to detect and debug than syntax or runtime errors, because they do not generate any error messages. You have to test the code with different inputs and outputs, and compare them with the expected results34 One try-except block may contain more than one except branch. A try-except block is a way of handling exceptions in Python, by using the keywords try and except. The try block contains the code that may raise an exception, and the except block contains the code that will execute if an exception occurs. You can have multiple except blocks for different types of exceptions, or for different actions to take. For example, you can write a try-except block like this:
try: # some code that may raise an exception except ValueError: # handle the ValueError exception except ZeroDivisionError: # handle the ZeroDivisionError exception except: # handle any other exception This way, you can customize the error handling for different situations, and provide more informative messages or alternative solutions5 The default (anonymous) except branch can be the last branch in the try-except block. The default except branch is the one that does not specify any exception type, and it will catch any exception that is not handled by the previous except branches. The default except branch can be the last branch in the try-except block, but it cannot be the first or the only branch. For example, you can write a try-except block like this:
try: # some code that may raise an exception except ValueError: # handle the ValueError exception except: # handle any other exception This is a valid try-except block, and the default except branch will be the last branch. However, you cannot write a try-except block like this:
try: # some code that may raise an exception except: # handle any exception This is an invalid try-except block, because the default except branch is the only branch, and it will catch all exceptions, even those that are not errors, such as KeyboardInterrupt or SystemExit. This is considered a bad practice, because it may hide or ignore important exceptions that should be handled differently or propagated further. Therefore, you should always specify the exception types that you want to handle, and use the default except branch only as a last resort5 Therefore, the correct answers are A. A tool that allows you to precisely trace program execution is called a debugger. and C. One try-except block may contain more than one except branch.

質問 # 17
What happens when the user runs the following code?

A. The code outputs 1.
B. The code outputs 3.
C. The code enters an infinite loop.
D. The code outputs 2.

正解：D

解説：
Explanation
The code snippet that you have sent is calculating the value of a variable "total" based on the values in the range of 0 to 3. The code is as follows:
total = 0 for i in range(0, 3): if i % 2 == 0: total = total + 1 else: total = total + 2 print(total) The code starts with assigning the value 0 to the variable "total". Then, it enters a for loop that iterates over the values 0, 1, and 2 (the range function excludes the upper bound). Inside the loop, the code checks if the current value of "i" is even or odd using the modulo operator (%). If "i" is even, the code adds 1 to the value of
"total". If "i" is odd, the code adds 2 to the value of "total". The loop ends when "i" reaches 3, and the code prints the final value of "total" to the screen.
The code outputs 2 to the screen, because the value of "total" changes as follows:
When i = 0, total = 0 + 1 = 1
When i = 1, total = 1 + 2 = 3
When i = 2, total = 3 + 1 = 4
When i = 3, the loop ends and total = 4 is printed
Therefore, the correct answer is B. The code outputs 2.

質問 # 18
Python Is an example of which programming language category?

A. machine
B. interpreted
C. compiled
D. assembly

正解：B

解説：
Explanation
Python is an interpreted programming language, which means that the source code is translated into executable code by an interpreter at runtime, rather than by a compiler beforehand. Interpreted languages are more flexible and portable than compiled languages, but they are also slower and less efficient. Assembly and machine languages are low-level languages that are directly executed by the hardware, while compiled languages are high-level languages that are translated into machine code by a compiler before execution.

質問 # 19
A set of rules which defines the ways in which words can be coupled in sentences is called:

A. lexis
B. syntax
C. dictionary
D. semantics

正解：B

解説：
Explanation
Syntax is the branch of linguistics that studies the structure and rules of sentences in natural languages. Lexis is the vocabulary of a language. Semantics is the study of meaning in language. A dictionary is a collection of words and their definitions, synonyms, pronunciations, etc.

質問 # 20
What is the expected output of the following code?

A. 0
B. 1
C. 2
D. 3

正解：B

解説：
Explanation
The code snippet that you have sent is using the count method to count the number of occurrences of a value in a list. The code is as follows:
my_list = [1, 2, 3, 4, 5] print(my_list.count(1))
The code starts with creating a list called "my_list" that contains the numbers 1, 2, 3, 4, and 5. Then, it uses the print function to display the result of calling the count method on the list with the argument 1. The count method is used to return the number of times a value appears in a list. For example, my_list.count(1) returns 1, because 1 appears once in the list.
The expected output of the code is 1, because the code prints the number of occurrences of 1 in the list.
Therefore, the correct answer is D. 1.

質問 # 21
Arrange the binary numeric operators in the order which reflects their priorities, where the top-most position has the highest priority and the bottom-most position has the lowest priority.

正解：

解説：

Explanation

The correct order of the binary numeric operators in Python according to their priorities is:
Exponentiation (**)
Multiplication (*) and Division (
Addition (+) and Subtraction (
This order follows the standard mathematical convention of operator precedence, which can be remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction). Operators with higher precedence are evaluated before those with lower precedence, but operators with the same precedence are evaluated from left to right. Parentheses can be used to change the order of evaluation by grouping expressions.
For example, in the expression 2 + 3 * 4 ** 2, the exponentiation operator (**) has the highest priority, so it is evaluated first, resulting in 2 + 3 * 16. Then, the multiplication operator (*) has the next highest priority, so it is evaluated next, resulting in 2 + 48. Finally, the addition operator (+) has the lowest priority, so it is evaluated last, resulting in 50.
You can find more information about the operator precedence in Python in the following references:
6. Expressions - Python 3.11.5 documentation
Precedence and Associativity of Operators in Python - Programiz
Python Operator Priority or Precedence Examples Tutorial

質問 # 22
Arrange the code boxes in the correct positions in order to obtain a loop which executes its body with the level variable going through values 5, 1, and 1 (in the same order).

正解：

解説：

質問 # 23
Which of the following functions can be invoked with two arguments?

正解：A

解説：
Explanation
The code snippets that you have sent are defining four different functions in Python. A function is a block of code that performs a specific task and can be reused in the program. A function can take zero or more arguments, which are values that are passed to the function when it is called. A function can also return a value or None, which is the default return value in Python.
To define a function in Python, you use the def keyword, followed by the name of the function and parentheses. Inside the parentheses, you can specify the names of the parameters that the function will accept.
After the parentheses, you use a colon and then indent the code block that contains the statements of the function. For example:
def function_name(parameter1, parameter2): # statements of the function return value To call a function in Python, you use the name of the function followed by parentheses. Inside the parentheses, you can pass the values for the arguments that the function expects. The number and order of the arguments must match the number and order of the parameters in the function definition, unless you use keyword arguments or default values. For example:
function_name(argument1, argument2)
The code snippets that you have sent are as follows:
A) def my_function(): print("Hello")
B) def my_function(a, b): return a + b
C) def my_function(a, b, c): return a * b * c
D) def my_function(a, b=0): return a - b
The question is asking which of these functions can be invoked with two arguments. This means that the function must have two parameters in its definition, or one parameter with a default value and one without.
The default value is a value that is assigned to a parameter if no argument is given for it when the function is called. For example, in option D, the parameter b has a default value of 0, so the function can be called with one or two arguments.
The only option that meets this criterion is option B. The function in option B has two parameters, a and b, and returns the sum of them. This function can be invoked with two arguments, such as my_function(2, 3), which will return 5.
The other options cannot be invoked with two arguments. Option A has no parameters, so it can only be called with no arguments, such as my_function(), which will print "Hello". Option C has three parameters, a, b, and c, and returns the product of them. This function can only be called with three arguments, such as my_function(2, 3, 4), which will return 24. Option D has one parameter with a default value, b, and one without, a, and returns the difference of them. This function can be called with one or two arguments, such as my_function(2) or my_function(2, 3), which will return 2 or -1, respectively.
Therefore, the correct answer is B. Option B.

質問 # 24
What is the expected result of the following code?

A. 0
B. The code is erroneous and cannot be run.
C. 1
D. 2

正解：B

解説：
Explanation
The code snippet that you have sent is trying to use the global keyword to access and modify a global variable inside a function. The code is as follows:
speed = 10 def velocity(): global speed speed = speed + 10 return speed print(velocity()) The code starts with creating a global variable called "speed" and assigning it the value 10. A global variable is a variable that is defined outside any function and can be accessed by any part of the code. Then, the code defines a function called "velocity" that takes no parameters and returns the value of "speed" after adding 10 to it. Inside the function, the code uses the global keyword to declare that it wants to use the global variable
"speed", not a local one. A local variable is a variable that is defined inside a function and can only be accessed by that function. The global keyword allows the function to modify the global variable, not just read it. Then, the code adds 10 to the value of "speed" and returns it. Finally, the code calls the function "velocity" and prints the result.
However, the code has a problem. The problem is that the code uses the global keyword inside the function, but not outside. The global keyword is only needed when you want to modify a global variable inside a function, not when you want to create or access it outside a function. If you use the global keyword outside a function, you will get a SyntaxError exception, which is an error that occurs when the code does not follow the rules of the Python language. The code does not handle the exception, and therefore it will terminate with an error message.
The expected result of the code is an unhandled exception, because the code uses the global keyword incorrectly. Therefore, the correct answer is A. The code is erroneous and cannot be run.

質問 # 25
Drag and drop the conditional expressions to obtain a code which outputs * to the screen.
(Note: some code boxes will not be used.)

正解：

解説：

Explanation

One possible way to drag and drop the conditional expressions to obtain a code which outputs * to the screen is:
if pool > 0:
print("*")
elif pool < 0:
print("**")
else:
print("***")
This code uses the if, elif, and else keywords to create a conditional statement that checks the value of the variable pool. Depending on whether the value is greater than, less than, or equal to zero, the code will print a different pattern of asterisks to the screen. The print function is used to display the output. The code is indented to show the blocks of code that belong to each condition. The code will output * if the value of pool is positive, ** if the value of pool is negative, and *** if the value of pool is zero.
You can find more information about the conditional statements and the print function in Python in the following references:
[Python If ... Else]
[Python Print Function]
[Python Basic Syntax]