PCAP Exceptions and File I/O — All Questions With Answers

Refer to the exhibit.

# error.log
2025-03-15 10:23:45 ERROR: Division by zero in module calc.py line 42
2025-03-15 10:23:46 WARNING: Low disk space on /dev/sda1
2025-03-15 10:23:47 INFO: User login successful

# Python code
try:
    with open('error.log', 'r') as f:
        for line in f:
            if 'ERROR' in line:
                raise RuntimeError(line.strip())
except RuntimeError as e:
    print('Error found:', e)

2025-04-01 10:23:45 ERROR root: Unhandled exception
Traceback (most recent call last):
  File "process.py", line 15, in <module>
    process_data()
  File "process.py", line 7, in process_data
    raise ValueError('Invalid value')
ValueError: Invalid value

try:
    with open('config.cfg', 'r') as f:
        data = f.read()
except FileNotFoundError:
    print('File not found')
except PermissionError:
    print('Permission denied')

[ERROR] 2025-01-01 12:00:00: Unhandled exception: ValueError: invalid literal for int() with base 10: 'abc'

try:
    with open('data.txt') as f:
        print(f.read())
except FileNotFoundError:
    try:
        with open('backup.txt') as f:
            print(f.read())
    except FileNotFoundError:
        print('No file found')

Refer to the exhibit.

Exhibit:
    def parse_value(data):
        try:
            value = int(data)
            return value
        except ValueError:
            return None
        except TypeError:
            return None
        except:
            return -1
    
    result = parse_value('abc')
    print(result)

Refer to the exhibit.

Exhibit:
    # log_output.txt contains:
    # INFO: Process started
    # ERROR: Disk full
    # WARN: Memory high
    # INFO: Process ended
    
    with open('log_output.txt', 'r') as f:
        for line in f:
            if 'ERROR' in line:
                print(line.strip())
    # Expected output: ERROR: Disk full

Refer to the exhibit.

Exhibit:
    try:
        with open('config.json', 'r') as f:
            data = json.load(f)
    except FileNotFoundError:
        print('Missing config file')
    except json.JSONDecodeError:
        print('Invalid JSON')
    except Exception:
        print('Unexpected error')

Traceback (most recent call last):
  File "script.py", line 5, in <module>
    f = open('data.txt', 'r')
FileNotFoundError: [Errno 2] No such file or directory: 'data.txt'

Traceback (most recent call last):
  File "app.py", line 10, in <module>
    raise ValueError('Invalid value')
ValueError: Invalid value

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "app.py", line 12, in <module>
    raise TypeError('Type mismatch') from None
TypeError: Type mismatch

file = open('test.txt', 'w')
file.write('Hello')
file.close()
print(file.closed)

def read_file():
    try:
        f = open('data.txt', 'r')
        return f.read()
    finally:
        f.close()

result = read_file()

try:
    f = open('data.txt', 'r')
    data = f.read()
    num = int(data)
except (ValueError, IOError) as e:
    print('Error:', e)
finally:
    f.close()

Config file: /etc/myapp/config.ini
[files]
input = /var/data/in.csv
output = /var/data/out.csv

Code:
config = configparser.ConfigParser()
config.read('/etc/myapp/config.ini')
with open(config['files']['input'], 'r') as f:
    lines = f.readlines()
    print(len(lines))

Traceback (most recent call last):
  File "script.py", line 5, in <module>
    open('nonexistent.txt', 'r')
FileNotFoundError: [Errno 2] No such file or directory: 'nonexistent.txt'

Code:
try:
    open('nonexistent.txt', 'r')
except OSError:
    print('OS error')
except FileNotFoundError:
    print('File not found')

try:
    x = 1 / 0
except ZeroDivisionError:
    print('A')
except:
    print('B')
else:
    print('C')
finally:
    print('D')

Refer to the exhibit.

# config.txt
[Settings]
host = localhost
port = 8080
debug = True

# Python code
import configparser

config = configparser.ConfigParser()
config.read('config.txt')
port = config.getint('Settings', 'port')
print(port)

Traceback (most recent call last):
  File "app.py", line 9, in <module>
    with open("config.json", "r") as f:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 'config.json'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "app.py", line 11, in <module>
    config = json.load(f)
             ^^^^^^^^^^^
NameError: name 'json' is not defined

{
  "logging": {
    "level": "DEBUG",
    "file": "/var/log/app.log"
  },
  "database": {
    "host": "localhost",
    "port": 5432
  }
}

with open('file.txt', 'r') as f:
    data = f.read()
    print(f.closed)
# Output: False

Traceback (most recent call last):
  File "test.py", line 3, in <module>
    raise ValueError("Invalid value")
ValueError: Invalid value

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "test.py", line 5, in <module>
    raise TypeError("Type mismatch") from None
TypeError: Type mismatch