Python and SQL Quiz

What will be the output of the following code? T = ('C', 'O', 'M', 'P', 'U', 'T', 'E', 'R') print(T[-2:-7:-2])

• ('R', 'T', 'P', 'O')

• ('E', 'U', 'M')

• ('O', 'M', 'P')

• ('M', 'P', 'U')

Answer explanation

The code uses slicing with a step of -2, starting from index -2 ('R') to -7 ('C'). The output is ('R', 'T', 'P', 'O'), as it selects every second element in reverse order from the specified range.

Which of the following is the correct syntax for string slicing in Python?

• str_name[start:end]

• str_name[start:step]

• str_name[step:end]

• str_name[step:start]

Answer explanation

The correct syntax for string slicing in Python is str_name[start:end], where 'start' is the index to begin slicing and 'end' is the index to stop (not inclusive). The other options incorrectly use 'step' or misplace 'start' and 'end'.

Which data type in Python is immutable?

• List

• Dictionary

• Set

• Tuple

Answer explanation

In Python, a tuple is an immutable data type, meaning its elements cannot be changed after creation. In contrast, lists, dictionaries, and sets are mutable, allowing modifications to their contents.

Which function is used to open a file in Python?

• open()

• read()

• write()

• fopen()

Answer explanation

The correct function to open a file in Python is open(). It allows you to specify the file name and mode (read, write, etc.). The other options, like read() and write(), are used for file operations after opening.

What does the len() function return in Python?

• Length of a string

• Number of elements in a list

• The number of characters in a file

• All of the above

Answer explanation

The len() function in Python returns the length of various data types, including the number of characters in a string, the number of elements in a list, and the number of characters in a file. Therefore, the correct answer is 'All of the above'.

Which of the following SQL commands is used to remove a table from a database?

• DROP DATABASE

• DELETE FROM

• DROP TABLE

• REMOVE TABLE

Answer explanation

The correct command to remove a table from a database is 'DROP TABLE'. 'DROP DATABASE' removes the entire database, 'DELETE FROM' removes rows from a table, and 'REMOVE TABLE' is not a valid SQL command.

What is the output of the following Python code? x = 3 def myfunc(): global x x += 2 print(x, end=' ') print(x, end=' ') myfunc() print(x, end=' ')

• 3 5 5

• 5 5 5

• 5 3 5

• 3 3 5

Answer explanation

Initially, x is 3. The first print(x) outputs 3. Inside myfunc(), x is incremented by 2, making it 5. The second print(x) outputs 5. After calling myfunc(), the final print(x) outputs 5. Thus, the output is 3 5 5.

Which Python exception is raised when a file is not found?

• SyntaxError

• FileNotFoundError

• ValueError

• KeyError

Answer explanation

The correct choice is FileNotFoundError, which is specifically raised in Python when an attempt to open a file fails because the file does not exist. Other options like SyntaxError and ValueError are unrelated to file operations.

What will the following code print? x = "abc" print(x[1:3])

• ab

• bc

• a

• abc

Answer explanation

The code prints the substring of 'abc' from index 1 to 3. Index 1 is 'b' and index 2 is 'c', so it outputs 'bc'. Therefore, the correct answer is 'bc'.

Which of the following Python statements is used to create a dictionary?

• d = {}

• d = dict()

• d = []

• Both A and B

Answer explanation

Both A (d = {}) and B (d = dict()) are valid ways to create an empty dictionary in Python. Option C (d = []) creates a list, not a dictionary. Therefore, the correct answer is Both A and B.