Question 1

When a Python program begins execution, it creates three xe "file object:standard"xe "standard file objects"standard file objects: $\bullet$sys.stdin-the standard input file object,
$\bullet$sys.stdout-the standard output file object, and
$\bullet$sys.stderr-the standard error file object.
You must import the sys module if you need to refer to these objects explicitly in your code, but this is rare. Which of the following statements is false?
A) Though these are considered file objects, they do not read from or write to files by default.
B) The input function implicitly uses sys.stdin to get user input from the keyboard.
C) Function print implicitly outputs to sys.stdout, which appears in the command line.
D) Python implicitly outputs program errors and tracebacks to sys.stdout.

Accepted Answer

Python implicitly outputs program errors and tracebacks to sys.stderr, not to sys.stdout.

Question 2

Which of the following statements are false?
A) The built-in open function opens a file and associates it with a xe "file object"file object.
B) The mode argument specifies the file-open mode, indicating whether to open a file for reading from the file, for writing to the file or both.
C) The mode 'w' xe "open a file:for writing"opens the file for writing, creating the file if it does not exist. If the file already exists, opening it for writing causes any new data to be appended to the end of the file.
D) At the end of the with statement's suite, the with statement implicitly calls the file object's close method to close the file.

Accepted Answer

Statement C is false because opening a file in 'w' mode for writing does not append to the end of the file if it already exists; instead, it truncates the file, starting from the beginning, which means any existing data in the file will be erased.

Question 3

Which of the following statements is false?
A) Many applications xe "resource:acquire"xe "acquire resources"acquire resources, such as files, network connections, database connections and more. You should xe "resource:release"xe "release resources"release resources when your application terminates.
B) The with statement acquires a resource and assigns its corresponding object to a variable.
C) The with statement allows the application to use the resource via that variable.
D) The with statement calls the resource object's xe "close method:of an object that uses a system resource"close method to release the resource when program control reaches the end of the with statement's suite.

Accepted Answer

The false statement is A because it suggests that resources should only be released when an application terminates, which is incorrect. Resources should be released as soon as they are no longer needed to avoid resource leaks and other potential issues.

Question 4

The json module's ________ function reads the entire JSON contents of its file object argument and converts the JSON into a Python object. This is known as ________ the data.
A) read, serializing
B) load, serializing
C) load, deserializing
D) read, deserializing

Accepted Answer

The json module's 'load' function reads the entire JSON contents of its file object argument and converts the JSON into a Python object. This process is known as deserializing the data. Hence, option C - load, deserializing - is the correct choice.

Question 5

Which of the following statements a), b) or c) is false?
A) You can use JSON to serialize and deserialize objects to facilitate saving those objects to secondary storage and transmitting them over the Internet.
B) There are security vulnerabilities to serializing and deserializing data with the Python Standard Library's pickle module.
C) The with statement automatically releases a resource at the end of the statement's suite.
D) All of the above statements are true.

Accepted Answer

All the statements provided are true. JSON is commonly used for serializing and deserializing objects for storage or transmission. The pickle module in Python is known for its security vulnerabilities when loading data from untrusted sources. The with statement in Python is used for resource management and automatically releases the resource when the block of code is exited.

Question 6

Which of the following statements a), b) or c) is false?
A) Variables, lists, tuples, dictionaries, sets, arrays, pandas Series and pandas DataFrames offer long-term data storage.
B) Computers store files on secondary storage devices, including xe "solid-state drive"solid-state drives, xe "hard disk"hard disks and more.
C) Some popular text file formats are plain text, xe "JSON (JavaScript Object Notation)"JSON (JavaScript Object Notation) and xe "CSV (comma-separated value) format"CSV (comma-separated values).
D) All of the above statements are true?

Accepted Answer

Variables, lists, tuples, dictionaries, sets, arrays, pandas Series, and pandas DataFrames are used for in-memory data storage and manipulation, not long-term data storage. Long-term storage is typically achieved through databases or file systems on secondary storage devices.

Question 7

Which of the following statements a), b) or c) is false?
A) The following code writes an object in JSON format to a file: import json
With open('accounts.json', 'w') as accounts:
Json.dump(accounts_dict, accounts)
B) The snippet in Part (a) opens the file accounts.json and uses the json module's dump function to serialize the dictionary accounts_dict into the file.
C) JSON delimits strings with double-quote characters.
D) All of the above statements are true.

Accepted Answer

All the statements provided are true: a) correctly describes a code snippet for writing an object in JSON format to a file using Python's json module, b) accurately explains the operation of the code in part a), and c) correctly states that JSON uses double-quote characters to delimit strings.

Question 8

Which of the following statements a), b) or c) is false?
A) JSON objects are similar to Python lists. Each xe "JSON (JavaScript Object Notation):JSON object"JSON object contains a comma-separated list of property names and values, in curly braces. For example, the following JSON object might represent a client record: {"account": 100, "name": "Jones", "balance": 24.98}
B) JSON also supports xe "JSON (JavaScript Object Notation):array"xe "array:JSON"arrays which, like Python lists, are comma-separated values in square brackets. For example, the following is an acceptable JSON array of numbers: [100, 200, 300]
C) Values in JSON objects and arrays can be xe "JSON (JavaScript Object Notation):string"xe "string built-in type:in JSON"strings in double quotes, numbers, JSON xe "JSON (JavaScript Object Notation):Boolean values"xe "Boolean values in JSON"Boolean values (xe "JSON (JavaScript Object Notation):true"true or xe "JSON (JavaScript Object Notation):false"false),xe "JSON (JavaScript Object Notation):null"xe "null in JSON" null (to represent no value, like None in Python), arrays and other JSON objects.
D) All of the above statements are true.

Accepted Answer

JSON objects are similar to Python dictionaries, not lists, as they consist of key-value pairs.

Question 9

The json module enables you to convert objects to xe "JSON (JavaScript Object Notation)"JSON (JavaScript Object Notation) text format. This is known as ________ the data.
A) chunking
B) calibrating
C) serializing
D) registering

Accepted Answer

The process of converting objects to JSON text format is known as serialization.

Question 10

Which of the following statements are false?
A) A file object's readlines method xe "read a file into a program"reads an entire text file and returns each line as a string in a list of strings.
B) Calling readlines for a large file can be a time-consuming operation, which must complete before you can begin using the list of strings.
C) Using the file object in a for statement enables your program to process each text line as it's read.
D) All of the above statements are true.

Accepted Answer

All of the statements are true.

Question 11

Which of the following statements is false?
A) For a text file, the read method returns a string containing the number of characters specified by the method's integer argument. For a binary file, the method returns the specified number of bytes. If no argument is specified, the method returns the entire contents of the file.
B) The readline method returns one line of text as a string, including the newline character if there is one.
C) The readline method issues an EndOfFileError when it encounters the end of the file.
D) The writelines method receives a list of strings and writes its contents to a file.

Accepted Answer

The readline method does not issue an EndOfFileError when it encounters the end of the file. Instead, it simply returns an empty string.

Question 12

Which of the following statements is false?
A) Attempting to divide by 0 results in a xe "ZeroDivisionError"ZeroDivisionError.
B) When a program attempts to divide by zero, the interpreter is said to raise an exception of type xe "ZeroDivisionError"ZeroDivisionError.
C) When an exception is raised in an interactive IPython session, it displays the exception's traceback, then terminates the IPython session.
D) If an exception occurs in a script, IPython terminates the script and displays the exception's traceback.

Accepted Answer

When an exception is raised in an interactive IPython session, it displays the exception's traceback, but it does not terminate the IPython session.

Question 13

Which of the following statements a), b) or c) is false?
A) Python views text files and binary files (for images, videos and more) as xe "sequence:of bytes"sequences of bytes.
B) As in lists and arrays, the first character in a text file and byte in a binary file is located at position 0, so in a file of n characters or bytes, the highest position number is n - 1.
C) For each file you open, Python creates a file object that you'll use to interact with the file.
D) All of the above statements are true.

Accepted Answer

The answer of Which of the following statements a), b)...

Question 14

Which of the following statements a), b) or c) is false?
A) The json module's dumps function returns a Python string representation of an object in JSON format.
B) Using dumps with load, you can read JSON from a file and display it in a nicely indented format-sometimes called "pretty printing" the JSON.
C) When the dumps function call includes the indent keyword argument, as in with open('accounts.json', 'r') as accounts:
Print(json.dumps(json.load(accounts), indent=4))
The string contains newline characters and indentation for pretty printing-you also can use indent with the dump function when writing to a file:
D) All of the above statements are true.

Accepted Answer

The answer of Which of the following statements a), b)...

Question 15

Which of the following statements are false?
A) Many libraries you'll use to interact with xe "cloud-based services"cloud-based services such as Twitter, IBM Watson and others communicate with your applications via JSON (JavaScript Object Notation) objects.
B) JSON is a dxe "JSON (JavaScript Object Notation):data-interchange format"xe "data-interchange format:JSON"ata-interchange format readable only by computers and used to represent objects (such as dictionaries, lists and more) as collections of name-value pairs.
C) JSON can represent objects of custom classes.
D) JSON has become the preferred data format for transmitting objects across platforms. This is especially true for invoking cloud-based xe "web service"web services, which are functions and methods that you call over the Internet.

Accepted Answer

JSON is a human-readable data interchange format used to represent objects as collections of name-value pairs. It is readable by both computers and humans. The other statements are true: many libraries use JSON to communicate with cloud-based services, JSON can represent objects of custom classes, and it has become the preferred data format for transmitting objects across platforms and invoking web services over the internet.

Question 16

If the contents of a file should not be modified, open the file for ________-another example of the xe "principle of least privilege"principle of least privilege. This prevents the program from accidentally modifying the file.
A) writing only
B) reading only
C) reading and writing
D) none of the above

Accepted Answer

The principle of least privilege states that a user or program should only be given the minimum privileges required to carry out its functions. If the contents of a file should not be modified, opening it for writing would violate this principle. Therefore, the file should be opened for reading only to prevent any accidental modification.

Question 17

Various types of exceptions can occur when you work with files. Which of the following statements a), b) or c) is false?
A) A FileNotFoundError occurs if you attempt to open a non-existent file for reading with the 'r' or 'r+' modes.
B) A PermissionsError occurs if you attempt an operation for which you do not have permission. This might occur if you try to open a file that your account is not allowed to access or create a file in a folder where your account does not have permission to write, such as where your computer's operating system is stored.
C) A LockedError (with the error message 'I/O operation on closed file.') occurs when you attempt to write to a file that has already been closed.
D) All of the above statements are true.

Accepted Answer

The statement "A LockedError (with the error message 'I/O operation on closed file.') occurs when you attempt to write to a file that has already been closed" is false. A LockedError typically occurs when multiple processes or threads attempt to access the same file at the same time and one process or thread locks the file, preventing the others from accessing it.

Question 18

Which of the following statements a), b) or c) is false?
A) The Python Standard Library's pickle module can serialize objects into the data formats of many popular programming languages.
B) Pickle has potential security issues.
C) If you write your own pickling and de-pickling code, pickling can be secure.
D) All of the above statements are true.

Accepted Answer

The Python Standard Library's pickle module is designed to serialize and deserialize objects within Python, not into the data formats of many popular programming languages.

Question 19

Which of the following statements a), b) or c) is false?
A) The file open modes for writing and appending raise a FileNotFoundError if the file does not exist.
B) Each text-file mode has a corresponding binary-file mode specified with b, as in 'rb' or 'wb+'.
C) You use binary-file modes for reading or writing binary files, such as images, audio, video, compressed ZIP files and many other popular custom file formats.
D) All of the above statements are true.

Accepted Answer

Statement A is false because the file open mode for appending ('a' or 'a+') does not raise a FileNotFoundError if the file does not exist; instead, it creates the file. The writing mode ('w' or 'w+'), however, will create a new file, overwriting the existing file if it exists, but does not raise a FileNotFoundError.

Question 20

Which of the following statements a), b) or c) is false?
A) Python imposes a convenient record structure on files.
B) The following code creates an accounts.txt file and writes five client records to the file. Generally, records in text files are stored one per line, so we end each record with a newline character: with open('accounts.txt', mode='w') as accounts:
Accounts.write('100 Jones 24.98
')
Accounts.write('200 Doe 345.67
')
Accounts.write('300 White 0.00
')
Accounts.write('400 Stone -42.16
')
Accounts.write('500 Rich 224.62
')
C) You can also write to a file with print (which automatically outputs a 
), as in print('100 Jones 24.98', file=accounts)
D) All of the above statements are true.

Accepted Answer

Python does not impose a specific record structure on files; the structure is determined by how the data is written to and read from the file.

Quiz 9: Files and Exceptions

Which of the following statements are false?

Which of the following statements is false?

The json module's function reads the entire JSON contents of its file object argument and converts the JSON into a Python object. This is known as the data.

Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?

The json module enables you to convert objects to xe "JSON (JavaScript Object Notation) "JSON (JavaScript Object Notation) text format. This is known as ________ the data.

Which of the following statements are false?

Which of the following statements is false?

Which of the following statements is false?

Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?

Which of the following statements are false?

If the contents of a file should not be modified, open the file for ________-another example of the xe "principle of least privilege"principle of least privilege. This prevents the program from accidentally modifying the file.

Various types of exceptions can occur when you work with files. Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?

Which of the following statements a) , b) or c) is false?