Ace PCPP-32-101 Certification with 71 Actual Questions [Q41-Q65]

The correct answers are C and D. The json.loads() function is used for JSON deserialization. It accepts a JSON-formatted string, bytes, or bytearray and converts that serialized JSON data into an equivalent Python object. For example, a JSON object becomes a Python dictionary, a JSON array becomes a Python list, JSON strings become Python strings, and JSON numbers become Python numeric values.
Option A describes json.dumps(), which takes Python data and serializes it into JSON text. Option B is also incorrect because returning a JSON string is the job of json.dumps(), not json.loads(). Therefore, json.loads() takes JSON text as input and returns a Python entity.

Explanation
A static method is a method that belongs to a class rather than an instance of the class. It is defined using the @staticmethod decorator and does not take a self or cls parameter. Static methods are often used to define utility functions that do not depend on the state of an instance or the class itself.

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.

ConfigParser is a built-in library in Python that allows you to read and write configuration files. The read method is used to read the configuration file which can be in any of the supported file formats, such as INI, YAML, and JSON. The read_dict method is used to read the configuration from a Python dictionary. The read_conf and read_str options are not valid methods in the ConfigParser module.
Therefore, the correct options to load a configuration using ConfigParser are A. read and D. read_string.
Reference: Official Python documentation on ConfigParser: https://docs.python.org/3/library/configparser.
html

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.
Reference:
Official Python documentation on socket.gaierror: https://docs.python.org/3/library/socket.html#socket.
gaierror

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.
Reference: Official Python documentation on socket programming: https://docs.python.org/3/library/socket.
html

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

A). It addresses a service deployed at localhost (the host where the code is run).
This statement is true because localhost is a special hostname that refers to the local machine or the current host where the code is run. It is equivalent to using the IP address 127.0.0.1, which is the loopback address of the network interface. By using localhost as the hostname, the invocation addresses a service that is deployed on the same machine as the client.
D). It addresses a service listening at port 3000.
This statement is true because port 3000 is the part of the URL that follows the colon after the hostname. It specifies the port number where the service is listening for incoming requests. A port number is a 16-bit integer that identifies a specific process or application on a host. By using port 3000, the invocation addresses a service that is listening at that port.
B). It addresses a service whose timeout is set to 3000 ms.
This statement is false because timeout is not a part of the URL, but a parameter that can be passed to the requests.get () function in Python. Timeout specifies how long to wait for the server to send data before giving up. It is measured in seconds, not milliseconds. By using timeout=3, the invocation sets the timeout to 3 seconds, not 3000 ms.
C). It addresses a service located at the following address local.host.com.
This statement is false because local.host.com is not the same as localhost. Local.host.com is a fully qualified domain name (FQDN) that consists of three parts: local, host, and com. It requires DNS resolution to map it to an IP address. Localhost, on the other hand, is a special hostname that does not require DNS resolution and always maps to 127.0.0.1. By using localhost as the hostname, the invocation does not address a service located at local.host.com.
References:
https://docs.python.org/3/library/requests.html : https://en.wikipedia.org/wiki/Localhost : https://en.
wikipedia.org/wiki/Port_(computer_networking) : https://en.wikipedia.org/wiki/Fully_qualified_domain_name

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

The correct answer is A because { 1 } is not valid JSON syntax. In JSON, curly braces represent an object, but an object must contain name-value pairs. Property names must be strings enclosed in double quotation marks, followed by a colon and a value, such as {“id”: 1}. The expression { 1 } contains a numeric value inside braces without a property name or colon, so it cannot be parsed as a JSON object. It is also not an array, because JSON arrays use square brackets, such as [1]. It is not an integer either, because the braces change the syntax. Therefore, this JSON string is erroneous.

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 provided code snippet defines a function f1 that accepts variable-length arguments using the *args and **kwargs syntax. The *args parameter allows for an arbitrary number of unnamed arguments to be passed to the function as a tuple, while the **kwargs parameter allows for an arbitrary number of named arguments to be passed to the function as a dictionary.
Therefore, the correct statement that best describes the code is:
The *args parameter holds a list of unnamed parameters, while the **kwargs parameter holds a dictionary of named parameters.

The correct answer is B. The ConfigParser.sections() method returns a list of section names, but it does not include the special DEFAULT section. Therefore, even though config[‘DEFAULT’] = {} is present, DEFAULT is excluded from the printed result. The code then creates three regular sections: mysql, postgresql, and redis. Assigning config[‘redis’] = config[‘postgresql’] creates or updates a separate section named redis using the values from the postgresql section; it does not duplicate the section name postgresql in the section list. Therefore, the output contains only the normal section names: [‘mysql’,
‘postgresql’, ‘redis’] .

Explanation
According to PEP 8 recommendations, the two best options are Option B and Option D.
Option B follows PEP 8’s suggestion that all lines should be limited to 79 characters and for longer blocks of text like docstrings or comments, the length should be limited to 72 characters1. Option D follows PEP 8’s conventions for writing good documentation strings (a.k.a. “docstrings”) which are immortalized in PEP
257. It suggests writing docstrings for all public modules, functions, classes, and methods2.

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 messagebox.askquestion() method in Python’s tkinter library displays a message box with a specified question and two response buttons labeled “Yes” and “No”. It returns a string indicating which button was selected – either “yes” or “no”.
This function is used to ask questions to the user that have only two options: YES or NO. It can be used to ask the user if they want to continue or if they want to submit something 1.

The unbind_all() method in Tkinter is used to remove all event bindings from a widget. It is a method of the widget object and can be called on any widget in the Tkinter application. Therefore, option A is the correct answer.
Option B is incorrect because the method can be called on any widget, not just the main window widget.
Option C is correct as unbind_all() does not take any parameters.
Option D is incorrect because the method only removes event bindings and does not cause the widgets to disappear.
So, the correct answers are A and C.
References:
Tkinter documentation: https://docs.python.org/3/library/tkinter.html#event-bindings Tkinter tutorial: https://www.python-course.eu/tkinter_events_binds.php

Explanation
The true statement related to PEP 257 is Option B. According to PEP 257, string literals occurring elsewhere in Python code may also act as documentation. They are not recognized by the Python bytecode compiler and are not accessible as runtime object attributes (i.e. not assigned to doc), but two types of extra docstrings may be extracted by software tools: String literals occurring immediately after a simple assignment at the top level of a module, class, or init method are called “attribute docstrings”. String literals occurring immediately after another docstring are called “additional docstrings”1.

Explanation
Option A is true because PEP 8 recommends avoiding extraneous whitespace immediately inside parentheses, brackets or braces 1.
Option C is true because PEP 8 recommends avoiding extraneous whitespace between a trailing comma and a following close parenthesis 1.

The two true statements related to PEP 8 programming recommendations for code writing are Option B and Option D .
Option B is true because PEP 8 recommends making object type comparisons using the isinstance() method instead of comparing types directly 1 .
Option D is true because PEP 8 recommends not writing string literals that rely on significant trailing whitespaces as they may be visually indistinguishable, and certain editors may trim them 1 .

C). The execute method is provided by the Cursor class
This statement is true because the execute method is one of the methods of the Cursor class in the sqlite3 module. The Cursor class represents an object that can execute SQL statements and fetch results from a database connection. The execute method takes an SQL query as an argument and executes it against the database. For example, cur = conn.cursor (); cur.execute (“SELECT * FROM table”) creates and executes a cursor object that selects all rows from a table.
D). The fetchone method returns None when no rows are available
This statement is true because the fetchone method is another method of the Cursor class in the sqlite3 module. The fetchone method fetches the next row of a query result set and returns it as a single tuple or None if no more rows are available. For example, row = cur.fetchone () fetches and returns one row from the cursor object or None if there are no more rows.

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.

The issue is method resolution order, commonly called MRO. In Python multiple inheritance, the interpreter must build a consistent linear inheritance path for the class. Here, B already inherits from A, meaning B must appear before A in the resolution order. However, class C(A, B) asks Python to resolve A before B. These two requirements conflict, so Python cannot create a valid MRO for class C.
This results in a TypeError related to inconsistent method resolution order. The absence of an
__init__() method is not a problem because Python supplies a default initializer. Also, C can inherit run() if the inheritance order is valid.

Explanation
The dump() method in the xml.etree.ElementTree module allows you to output a debug representation of an XML tree to a file or standard output. This method is useful for analyzing the structure of the tree and tracking down errors.