Phython MCQ 12

Which of the following is an invalid datatype in Python?

• Set

• None

• Integer

• Real

Answer explanation

In Python, 'Real' is not a valid datatype. The valid datatypes include Set, None, and Integer. 'Real' is often used in mathematical contexts but does not exist as a specific datatype in Python.

Given the following dictionaries

dict_exam={"Exam":"AISSCE", "Year":2023}

dict_result={"Total":500, "Pass_Marks":165}

Which statement will merge the contents of both dictionaries?

• dict_exam.update(dict_result)

• dict_exam + dict_result

• dict_exam.add(dict_result)

• dict_exam.merge(dict_result)

Answer explanation

The correct choice is 'dict_exam.update(dict_result)', which merges the contents of both dictionaries into 'dict_exam'. The other options are invalid methods for merging dictionaries in Python.

Consider the given expression: not True and False or True Which of the following will be correct output if the given expression is evaluated?

• True

• False

• NONE

• NULL

Answer explanation

The expression evaluates as follows: not True is False, so it becomes False and False or True. False and False is False, and False or True is True. Therefore, the correct output is True.

Select the correct output of the code:

a = "Year 2022 at All the best"

a = a.split('2')

b = a[0] + ". " + a[1] + ". " + a[3]

print (b)

• Year . 0. at All the best

• Year 0. at All the best

• Year . 022. at All the best

• Year . 0. at all the best

Answer explanation

The code splits the string 'Year 2022 at All the best' by '2', resulting in ['Year ', '0', '22', ' at All the best']. The output concatenates the first, second, and fourth elements, yielding 'Year . 0. at All the best'.

Which of the following mode in file opening statement results or generates an error if the file does not exist? (a) (b) (c) (d)

• a+

• r+

• w+

• None of the above

Answer explanation

The 'r+' mode opens a file for reading and writing, and it requires the file to exist. If the file does not exist, it generates an error. In contrast, 'w+' creates a new file if it doesn't exist, and 'a+' appends to a file.

Fill in the blank: ______ command is used to remove primary key from a table in SQL.

• update

• remove

• alter

• drop

Answer explanation

The correct command to remove a primary key from a table in SQL is 'alter'. The 'alter' command allows you to modify an existing table structure, including dropping constraints like primary keys.

Which of the following commands will delete the table from MYSQL database?

• DELETE TABLE

• DROP TABLE

• REMOVE TABLE

• ALTER TABLE

Answer explanation

The correct command to delete a table in MySQL is 'DROP TABLE'. 'DELETE TABLE' and 'REMOVE TABLE' are not valid SQL commands, while 'ALTER TABLE' is used to modify an existing table, not delete it.

Which of the following statement(s) would give an error after executing the following code?

S="Welcome to class XII" # Statement 1

print(S) # Statement 2

S="Thank you" # Statement 3

S[0]= '@' # Statement 4

S=S+"Thank you" # Statement 5

• Statement 3

• Statement 4

• Statement 5

• Statement 4 and 5

Answer explanation

Statement 4 gives an error because strings in Python are immutable, meaning you cannot change an individual character. Statements 3 and 5 execute without errors, as they involve reassigning the string or concatenating.

Fill in the blank: _________ is a non-key attribute, whose values are derived from the primary key of some other table.

• Primary Key

• Foreign Key

• Candidate Key

• Alternate Key

Answer explanation

A Foreign Key is a non-key attribute in one table that links to the primary key of another table, establishing a relationship between the two. This makes it the correct choice for the blank.

Fill in the blank: The SELECT statement when combined with __________ clause, returns records without repetition.

• DESCRIBE

• UNIQUE

• DISTINCT

• NULL

Answer explanation

The correct choice is 'DISTINCT'. In SQL, the SELECT statement combined with the DISTINCT clause retrieves unique records, eliminating any duplicates from the result set.