[更新されたのは2023年]Python Institute PCPP-32-101問題準備には無料サンプルのPDF [Q14-Q33]

Explanation
The socket.gaierror exception is raised when an address-related error caused by the getaddrinfo() and getnameinfo() functions occurs. These functions are used to translate hostnames to IP addresses and vice versa, and the gaierror exception is raised if they fail to perform this translation.

Explanation
The true statement about the __name__ attribute is D. name is a special attribute, which is inherent for classes, and it contains the name of a class. The __name__ attribute is a special attribute of classes that contains the name of the class as a string.
The __name__ attribute is a special attribute in Python that is available for all classes, and it contains the name of the class as a string. The __name__ attribute can be accessed from both the class and its instances using the dot notation.

Explanation
Option B is correct because it sets the font option of the button to a tuple containing the font family (‘Arial’), size (12), and style (‘italic’).
Option C is correct because it sets the font option of the button to a string containing the font family (‘Arial’), size (12), and style (‘italic’) separated by spaces.

Explanation
In the given code snippet, the repeat function is a decorator that takes an argument num_times specifying the number of times the decorated function should be called. The repeat function returns an inner function wrapper_repeat that takes a function func as an argument and returns another inner function wrapper that calls func num_times times.
The provided code snippet represents an example of a decorator that accepts its own arguments.
The @decorator_function syntax is used to apply the decorator_function to the some_function function.
The decorator_function takes an argument arg1 and defines an inner function wrapper_function that takes the original function func as its argument. The wrapper_function then returns the result of calling func, along with the arg1 argument passed to the decorator_function.
Here is an example of how to use this decorator with some_function:
@decorator_function(“argument 1”)
defsome_function():
return”Hello world”
When some_function is called, it will first be passed as an argument to the decorator_function.
The decorator_function then adds the string “argument 1” to the result of calling some_function() and returns the resulting string. In this case, the final output would be “Hello world argument 1”.

Explanation
A socket object is usually created using the socket() constructor provided by the socket module in Python. The correct invocation is socket.socket(socket_domain, socket_type). This creates a new socket object with the specified socket domain and type.

Explanation
A socket is a connection point that enables a two-way communication between programs running in a network.
This statement is true because a socket is a software structure that serves as an endpoint for sending and receiving data across a network. A socket is defined by an application programming interface (API) for the networking architecture, such as TCP/IP. A socket can be used to establish a communication channel between two programs running on the same or different network nodes12.
A socket is always the secure means by which computers on a network can safely communicate, without the risk of exposure to an attack.
This statement is false because a socket by itself does not provide any security or encryption for the data transmitted over the network. A socket can be vulnerable to various types of attacks, such as eavesdropping, spoofing, hijacking, or denial-of-service. To ensure secure communication, a socket can use additional protocols or mechanisms, such as SSL/TLS, SSH, VPN, or firewall3.
A socket is a connection point that enables a one-way communication only between remote processes.
This statement is false because a socket can enable both one-way and two-way communication between processes running on the same or different network nodes. A socket can be used for connection-oriented or connectionless communication, depending on the type of protocol used. For example, TCP is a connection-oriented protocol that provides reliable and bidirectional data transfer, while UDP is a connectionless protocol that provides unreliable and unidirectional data transfer12.
A socket can be used to establish a communication endpoint for processes running on the same or different machines.
This statement is true because a socket can be used for inter-process communication (IPC) within a single machine or across different machines on a network. A socket can use different types of addresses to identify the processes involved in the communication, such as IP address and port number for network sockets, or file name or path for Unix domain sockets12.
References:
1: https://en.wikipedia.org/wiki/Network_socket 2:
https://www.geeksforgeeks.org/socket-in-computer-network/ 3:
https://www.tutorialspoint.com/what-is-a-network-socket-computer-networks

Explanation
The socket.gaierror exception is raised when an address-related error caused by the getaddrinfo() and getnameinfo() functions occurs. These functions are used to translate hostnames to IP addresses and vice versa, and the gaierror exception is raised if they fail to perform this translation.

Explanation
To test whether two variables refer to the same object in memory, you should use the is operator.
The is operator returns True if the two variables point to the same object in memory, and False otherwise.
For example:
a = [1, 2, 3]
b = a
c = [1, 2, 3]
print(a is b) # True
print(a is c) # False
In this example, a and b refer to the same list object in memory, so a is b returns True. On the other hand, a and c refer to two separate list objects with the same values, so a is c returns False.

Explanation
The cget() method in Python is used to read the configuration options of a widget in Tkinter. It retrieves the value of a specified configuration option for a Tkinter widget. Hence, option A is the correct answer.

Explanation
The @property decorator should be defined after the method that is responsible for setting an encapsulated attribute is a false sentence. In fact, the @property decorator should be defined before the method that is used to set the attribute value. The @property decorator and the setter and deleter methods work together to create an encapsulated attribute, which is used to provide control over the attribute’s value.

Explanation
If you do not define the quoting argument in the writer method provided by the csv module, the default quoting behavior is set to QUOTE_MINIMAL. This means that fields containing special characters such as the delimiter or newline character will be quoted, while fields that do not contain special characters will not be quoted.

Explanation
Option B is true because the unbind() method is invoked from within a widget’s object 1.
Option D is true because the unbind() method needs the event name as an argument 1.
The unbind() method in Tkinter is used to remove a binding between an event and a function. It can be invoked from within a widget’s object when a binding is no longer needed. The method requires the event name as an argument to remove the binding for that specific event. For example:
button = tk.Button(root, text=”Click me”)
button.bind(“<Button-1>”, callback_function) # bind left mouse click event to callback_function button.unbind(“<Button-1>”) # remove the binding for the left mouse click event

Explanation
w.resizable()
The resizable() method takes two Boolean arguments, width and height, that specify whether the main window can be resized in the corresponding directions. Passing False to both arguments makes the main window non-resizable, whereas passing True to both arguments (or omitting them) makes the window resizable.
Here is an example that sets the dimensions of the main window to 500×400 pixels and makes it non-resizable:
importtkinter as tk
root = tk.Tk()
root.geometry(“500×400”)
root.resizable(False, False)
root.mainloop()
References:
* Tkinter documentation: https://docs.python.org/3/library/tk.html
* Tkinter tutorial: https://www.python-course.eu/python_tkinter.php
The resizable () method of a tkinter window object allows you to specify whether the window can be resized by the user in the horizontal and vertical directions. You can pass two boolean arguments to this method, such as w.resizable (False, False), to prevent both dimensions from being changed. Alternatively, you can pass 0 or
1 as arguments, such as w.resizable (0, 0), to achieve the same effect1.
References:
1: https://stackoverflow.com/questions/36575890/how-to-set-a-tkinter-window-to-a-constant-size Other methods that can be used to control the window size are:
* w.geometry () : This method allows you to set the initial size and position of the window by passing a string argument in the format “widthxheight+x+y”, such as w.geometry (“500×500+100+100”)12.
* w.minsize () and w.maxsize (): These methods allow you to set the minimum and maximum size of the window in pixels, such as w.minsize (500, 500) and w.maxsize (1000, 1000)12.
* w.pack_propagate () and w.grid_propagate (): These methods allow you to enable or disable the propagation of the size of the widgets inside the window to the window itself. By default, these methods are set to True, which means that the window will adjust its size according to the widgets it contains.
You can set these methods to False or 0 to prevent this behavior, such as w.pack_propagate (0) or w.grid_propagate (0).
* w.place (): This method allows you to place the window at a specific position and size relative to its parent window or screen. You can use keyword arguments such as x, y, width, height, relx, rely, relwidth, and relheight to specify the coordinates and dimensions of the window in absolute or relative terms, such as w.place (x=0, y=0, relwidth=1, relheight=1).
References:
2: https://stackoverflow.com/questions/25690423/set-window-dimensions-in-tkinter-python-3 :
https://stackoverflow.com/questions/36575890/how-to-set-a-tkinter-window-to-a-constant-size/36576068#36576
https://www.skotechlearn.com/2020/06/tkinter-window-position-size-center-screen-in-python.html

Explanation
The correct answer is B. The getNumberofCrosswords() method should be decorated with @classmethod. In the given code snippet, the getNumberofCrosswords method is intended to be a class method that returns the value of the numberofcrosswords class variable. However, the method is not decorated with the @classmethod decorator and does not take a cls parameter representing the class itself. To make getNumberofCrosswords a proper class method, it should be decorated with @classmethod and take a cls parameter as its first argument.
The getNumberofCrosswords() method should be decorated with @classmethod.
This is because the getNumberofCrosswords() method is intended to access the class-level variable numberofcrosswords, but it is defined as an instance method, which requires an instance of the class to be created before it can be called. To make it work as a class-level method, you can define it as a class method by adding the @classmethod decorator to the function.
Here’s an example of how to define getNumberofCrosswords() as a class method:
classCrossword:
numberofcrosswords =0
def __init__(self, author, title):
self.author = author
self.title = title
Crossword.numberofcrosswords +=1
@classmethod
defgetNumberofCrosswords(cls):
returncls.numberofcrosswords
In this example, getNumberofCrosswords() is defined as a class method using the @classmethod decorator, and the cls parameter is used to access the class-level variable numberofcrosswords.

Explanation
The json.dumps() function is used to convert a Python object into a JSON string 1. It takes Python data as its argument, such as a dictionary or a list, and returns a JSON string.

Explanation
Composition is an object-oriented design concept that models a has-a relationship. In composition, a class known as composite contains an object of another class known as component. In other words, a composite class has a component of another class1.
Composition allows a class to be projected as a container of different classes.
Composition is a concept in Python that allows for building complex objects out of simpler objects, by aggregating one or more objects of another class as attributes. The objects that are aggregated are generally considered to be parts of the whole object, and the containing object is often viewed as a container for the smaller objects.
In composition, objects are combined in a way that allows for greater flexibility and modifiability than what inheritance can offer. With composition, it is possible to create new objects by combining existing objects, by using a container object to host other objects. By contrast, with inheritance, new objects extend the behavior of their parent classes, and are limited by that inheritance hierarchy.
References:
* Official Python documentation on
Composition: https://docs.python.org/3/tutorial/classes.html#composition
* GeeksforGeeks article on Composition vs
Inheritance: https://www.geeksforgeeks.org/composition-vs-inheritance-python/
* Real Python article on Composition and
Inheritance: https://realpython.com/inheritance-composition-python/

Explanation
In the context of TCP/IP networks, the communication side that initiates a connection is called the client, whereas the side that answers the client is called the server.
This statement is true because TCP/IP networks use a client-server model to establish connection-oriented communications. The client is the device or application that requests a service or resource from another device or application, which is called the server. The server responds to the client’s request and provides the service or resource.For example, when you browse a website using a web browser, the browser acts as a client and sends a request to the web server that hosts the website. The web server acts as a server and sends back the requested web page to the browser1.
Connectionless communications are usually built on top of TCP.
This statement is false because TCP (Transmission Control Protocol) is a connection-oriented protocol that requires establishing and terminating a connection before and after sending data. Connectionless communications are usually built on top of UDP (User Datagram Protocol), which is a connectionless protocol that does not require any connection setup or teardown. UDP simply sends data packets to the destination without checking if they are received or not2.
Using walkie-talkies is an example of a connection-oriented communication.
This statement is false because using walkie-talkies is an example of a connectionless communication.
Walkie-talkies do not establish a dedicated channel or connection between the sender and receiver before transmitting data. They simply broadcast data over a shared frequency without ensuring that the receiver is ready or available to receive it. The sender does not know if the receiver has received the data or not3.
A phone call is an example of a connection-oriented communication.
This statement is true because a phone call is an example of a connection-oriented communication. A phone call requires setting up a circuit or connection between the caller and callee before exchanging voice data. The caller and callee can hear each other’s voice and know if they are connected or not. The phone call also requires terminating the connection when the conversation is over4.
References:
1: https://www.techtarget.com/searchnetworking/definition/client-server 2:
https://www.javatpoint.com/connection-oriented-vs-connectionless-service 3:
https://en.wikipedia.org/wiki/Walkie-talkie 4: https://en.wikipedia.org/wiki/Telephone_call A is true because in the context of TCP/IP networks, the communication side that initiates a connection is called the client, and the side that answers the client is called the server. This is the basis for establishing a connection-oriented communication.
D is true because a phone call is an example of a connection-oriented communication. Like TCP/IP, a phone call establishes a connection between two devices (in this case, two phones) before communication can occur.
A is true because in the context of TCP/IP networks, the communication side that initiates a connection is called the client, and the side that answers the client is called the server. This is the basis for establishing a connection-oriented communication.
D is true because a phone call is an example of a connection-oriented communication. Like TCP/IP, a phone call establishes a connection between two devices (in this case, two phones) before communication can occur.
B is false because connectionless communications are usually built on top of UDP, not TCP. UDP is a connectionless protocol that does not establish a connection before sending data.
C is false because using walkie-talkies is an example of a connectionless communication. Walkie-talkies do not establish a connection before communication begins, and messages are simply broadcasted to all devices within range.
Here is a sample code in Python using the socket module to create a TCP server and client to demonstrate the connection-oriented communication:
Server-side code:
importsocket
HOST =’127.0.0.1′
PORT =8080
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print(‘Connected by’, addr)
whileTrue:
data = conn.recv(1024)
ifnotdata:
break
conn.sendall(data)
Client-side code:
importsocket
HOST =’127.0.0.1′
PORT =8080
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b’Hello, world’)
data = s.recv(1024)
print(‘Received’,repr(data))
The server listens for incoming connections on port 8080, and when a connection is established, it prints the address of the client that has connected. The server then continuously receives data from the client and sends it back to the client until the connection is closed.
The client establishes a connection with the server and sends the message “Hello, world” encoded as bytes. It then waits for a response from the server and prints the data it receives.

Explanation
If the main window is too small to fit all its widgets, some widgets may be invisible. So, the correct answer is Option A.
When a window is not large enough to display all of its content, some widgets may be partially or completely hidden. The window will not automatically expand to fit all of its content, and no exception will be raised. The widgets will not be automatically scaled down to fit the window’s size.
If the main window is too small to fit all its widgets, some of the widgets may not be visible or may be partially visible. This is because the main window has a fixed size, and if there are more widgets than can fit within that size, some of them will be outside the visible area of the window.
To avoid this issue, you can use layout managers such as grid, pack, or place to dynamically adjust the size and position of the widgets as the window changes size. This will ensure that all the widgets remain visible and properly arranged regardless of the size of the main window.
References:
* https://www.tkdocs.com/tutorial/widgets.html#managers
* https://www.geeksforgeeks.org/python-tkinter-widgets/
* https://anzeljg.github.io/rin2/book2/2405/docs/tkinter/introduction.html