310+ Problem Solving and Python Programming Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Computer Science Engineering (CSE) , Information Technology Engineering (IT) , Electrical Engineering , Civil Engineering , Mechanical Engineering .

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201.	Write the list comprehension to pick out only negative integers from a given list ‘l’.
A.	[x<0 in l]
B.	[x for x<0 in l]
C.	[x in l for x<0]
D.	[x for x in l if x<0]
Answer» D. [x for x in l if x<0]
Explanation: to pick out only the negative numbers from a given list ‘l’, the correct list comprehension statement would be: [x for x in l if x<0].

202.	=[x+y for x, y in zip(l1, l2)] l3
A.	error
B.	0
C.	[-20, -60, -80]
D.	[0, 0, 0]
Answer» D. [0, 0, 0]
Explanation: the code shown above returns x+y, for x belonging to the list l1 and y belonging to the list l2. that is, l3=[10-10, 20-20, 30-20], which is, [0, 0, 0].

203.	Write a list comprehension for number and its cube for l=[1, 2, 3, 4, 5, 6, 7, 8, 9].
A.	[x**3 for x in l]
B.	[x^3 for x in l]
C.	[x**3 in l]
D.	[x^3 in l]
Answer» A. [x**3 for x in l]
Explanation: the list comprehension to print

204.	Write a list comprehension for producing a list of numbers between 1 and 1000 that are divisible by 3.
A.	[x in range(1, 1000) if x%3==0]
B.	[x for x in range(1000) if x%3==0]
C.	[x%3 for x in range(1, 1000)]
D.	[x%3=0 for x in range(1, 1000)]
Answer» B. [x for x in range(1000) if x%3==0]
Explanation: the list comprehension [x for x in range(1000) if x%3==0] produces a list of numbers between 1 and 1000 that are divisible by 3.

205.	Write a list comprehension to produce the list: [1, 2, 4, 8, 16……212].
A.	[(2**x) for x in range(0, 13)]
B.	[(x**2) for x in range(1, 13)]
C.	[(2**x) for x in range(1, 13)]
D.	[(x**2) for x in range(0, 13)]
Answer» A. [(2**x) for x in range(0, 13)]
Explanation: the required list comprehension will print the numbers from 1 to 12, each raised to 2. the required answer is thus, [(2**x) for x in range(0, 13)].

206.	What is the data type of (1)?
A.	tuple
B.	integer
C.	list
D.	both tuple and integer
Answer» B. integer
Explanation: a tuple of one element must be created as (1,).

207.	What type of data is: a=[(1,1),(2,4),(3,9)]?
A.	array of tuples
B.	list of tuples
C.	tuples of lists
D.	invalid type
Answer» B. list of tuples
Explanation: the variable a has tuples enclosed in a list making it a list of tuples.

208.	Is the following Python code valid? >>> a,b=1,2,3
A.	yes, this is an example of tuple unpacking. a=1 and b=2
B.	yes, this is an example of tuple unpacking. a=(1,2) and b=3
C.	no, too many values to unpack
D.	yes, this is an example of tuple unpacking. a=1 and b=(2,3)
Answer» C. no, too many values to unpack
Explanation: for unpacking to happen, the number of values of the right hand side must be equal to the number of variables on the left hand side.

209.	Tuples can’t be made keys of a dictionary.
A.	true
B.	false
Answer» B. false
Explanation: tuples can be made keys of a dictionary because they are hashable.

210.	Which of the following statements create a dictionary?
A.	d = {}
B.	d = {“john”:40, “peter”:45}
C.	d = {40:”john”, 45:”peter”}
D.	all of the mentioned
Answer» D. all of the mentioned
Explanation: dictionaries are created by specifying keys and values.

211.	Suppose d = {“john”:40, “peter”:45}, to delete the entry for “john” what command do we use?
A.	d.delete(“john”:40)
B.	d.delete(“john”)
C.	del d[“john”]
D.	del d(“john”:40)
Answer» C. del d[“john”]
Explanation: execute in the shell to verify.

213.	print(list(d.keys()))
A.	[“john”, “peter”]
B.	[“john”:40, “peter”:45]
C.	(“john”, “peter”)
D.	(“john”:40, “peter”:45)
Answer» A. [“john”, “peter”]
Explanation: the output of the code shown above is a list containing only keys of the dictionary d, in the form of a list.

215.	Which of the following is not a declaration of the dictionary?
A.	{1: ‘a’, 2: ‘b’}
B.	dict([[1,”a”],[2,”b”]])
C.	{1,”a”,2”b”}
D.	{ }
Answer» C. {1,”a”,2”b”}
Explanation: option c is a set, not a dictionary.

218.	If a is a dictionary with some key-value pairs, what does a.popitem() do?
A.	removes an arbitrary element
B.	removes all the key-value pairs
C.	removes the key-value pair for the key given as an argument
D.	invalid method for dictionary
Answer» A. removes an arbitrary element
Explanation: the method popitem() removes a random key-value pair.

220.	To open a file c:\scores.txt for writing, we use
A.	outfile = open(“c:\\scores.txt”, “w”)
B.	outfile = open(“c:\\scores.txt”, “w”)
C.	outfile = open(file = “c:\\scores.txt”, “w”)
D.	outfile = open(file = “c:\\scores.txt”, “w”)
Answer» B. outfile = open(“c:\\scores.txt”, “w”)
Explanation: w is used to indicate that file is to be written to.

212.	Suppose d = {“john”:40, “peter”:45}. To obtain the number of entries in dictionary which command do we use?
A.	d.size()
B.	len(d)
C.	size(d)
D.	d.len()
Answer» B. len(d)
Explanation: execute in the shell to verify.

214.	Which of these about a dictionary is false?
A.	the values of a dictionary can be accessed using keys
B.	the keys of a dictionary can be accessed using values
C.	dictionaries aren’t ordered
D.	dictionaries are mutable
Answer» B. the keys of a dictionary can be accessed using values
Explanation: the values of a dictionary can be accessed using keys but the keys of a dictionary can’t be accessed using values.

216.	Which of the following isn’t true about dictionary keys?
A.	more than one key isn’t allowed
B.	keys must be immutable
C.	keys must be integers
D.	when duplicate keys encountered, the last assignment wins
Answer» C. keys must be integers
Explanation: keys of a dictionary may be any data type that is immutable.

217.	Which of the statements about dictionary values if false?
A.	more than one key can have the same value
B.	the values of the dictionary can be accessed as dict[key]
C.	values of a dictionary must be unique
D.	values of a dictionary can be a mixture of letters and numbers
Answer» C. values of a dictionary must be unique
Explanation: more than one key can have the same value.

219.	If b is a dictionary, what does any(b) do?
A.	returns true if any key of the dictionary is true
B.	returns false if dictionary is empty
C.	returns true if all keys of the dictionary are true
D.	method any() doesn’t exist for dictionary
Answer» A. returns true if any key of the dictionary is true
Explanation: method any() returns true if any key of the dictionary is true and false if the dictionary is empty.

221.	To open a file c:\scores.txt for appending data, we use
A.	outfile = open(“c:\\scores.txt”, “a”)
B.	outfile = open(“c:\\scores.txt”, “rw”)
C.	outfile = open(file = “c:\\scores.txt”, “w”)
D.	outfile = open(file = “c:\\scores.txt”, “w”)
Answer» A. outfile = open(“c:\\scores.txt”, “a”)
Explanation: a is used to indicate that data is to be appended.

222.	Which of the following statements are true?
A.	when you open a file for reading, if the file does not exist, an error occurs
B.	when you open a file for writing, if the file does not exist, a new file is created
C.	when you open a file for writing, if the file exists, the existing file is overwritten with the new file
D.	all of the mentioned
Answer» D. all of the mentioned
Explanation: the program will throw an error.

223.	1 TEXT FILES, READING AND WRITING FILES, FORMAT OPERATOR
A.	infile.read(2)
B.	infile.read()
C.	infile.readline()
D.	infile.readlines()
Answer» A. infile.read(2)
Explanation: execute in the shell to verify.

224.	print(f.closed)
A.	true
B.	false
C.	none
D.	error
Answer» A. true
Explanation: the with statement when used with open file guarantees that the file object is closed when the with block exits.

225.	Which are the two built-in functions to read a line of text from standard input, which by default comes from the keyboard?
A.	raw_input & input
B.	input & scan
C.	scan & scanner
D.	scanner
Answer» A. raw_input & input
Explanation: python provides two built-in functions to read a line of text from standard input, which by default comes from the keyboard. these functions are:

310+ Problem Solving and Python Programming Solved MCQs

Write the list comprehension to pick out only negative integers from a given list ‘l’.

=[x+y for x, y in zip(l1, l2)] l3

Write a list comprehension for number and its cube for l=[1, 2, 3, 4, 5, 6, 7, 8, 9].

Write a list comprehension for producing a list of numbers between 1 and 1000 that are divisible by 3.

Write a list comprehension to produce the list: [1, 2, 4, 8, 16……212].

What is the data type of (1)?

What type of data is: a=[(1,1),(2,4),(3,9)]?

Is the following Python code valid? >>> a,b=1,2,3

Tuples can’t be made keys of a dictionary.

Which of the following statements create a dictionary?

Suppose d = {“john”:40, “peter”:45}, to delete the entry for “john” what command do we use?

Suppose d = {“john”:40, “peter”:45}. To obtain the number of entries in dictionary which command do we use?

print(list(d.keys()))

Which of these about a dictionary is false?

Which of the following is not a declaration of the dictionary?

Which of the following isn’t true about dictionary keys?

Which of the statements about dictionary values if false?

If a is a dictionary with some key-value pairs, what does a.popitem() do?

If b is a dictionary, what does any(b) do?

To open a file c:\scores.txt for writing, we use

To open a file c:\scores.txt for appending data, we use

Which of the following statements are true?

1 TEXT FILES, READING AND WRITING FILES, FORMAT OPERATOR

print(f.closed)

Which are the two built-in functions to read a line of text from standard input, which by default comes from the keyboard?

Which one of the following is not attributes of file?

What is the use of tell() method in python?

What is the current syntax of rename() a file?

fo.close()

What is the use of seek() method in files?

What is the use of truncate() method in file?

Which is/are the basic I/O connections in file?

sys.stdout.write('Python\n')

What is the pickling?

What is unpickling?

What is the correct syntax of open() function?

fo.close()

Correct syntax of file.writelines() is?

Correct syntax of file.readlines() is?

In file handling, what does this terms means “r, a”?

What is the use of “w” in file handling?

What is the use of “a” in file handling?

Which function is used to read all the characters?

Which function is used to read single line from file?

Which function is used to write all the characters?

Which function is used to write a list of string in a file?

Which function is used to close a file in python?

Is it possible to create a text file in python?

Which of the following are the modes of both writing and reading in binary format in file?

Which of the following is not a valid mode to open a file?

226.	Which one of the following is not attributes of file?
A.	closed
B.	softspace
C.	rename
D.	mode
Answer» C. rename
Explanation: rename is not the attribute of file rest all are files attributes.

227.	What is the use of tell() method in python?
A.	tells you the current position within the file
B.	tells you the end position within the file
C.	tells you the file is opened or not
D.	none of the mentioned
Answer» A. tells you the current position within the file
Explanation: the tell() method tells you the current position within the file; in other words, the next read or write will occur at that many bytes from the beginning of the file.

228.	What is the current syntax of rename() a file?
A.	rename(current_file_name, new_file_name)
B.	rename(new_file_name, current_file_name,)
C.	rename(()(current_file_name, new_file_name))
D.	none of the mentioned
Answer» A. rename(current_file_name, new_file_name)
Explanation: this is the correct syntax which has shown below.

229.	fo.close()
A.	compilation error
B.	syntax error
C.	displays output
D.	none of the mentioned
Answer» C. displays output
Explanation: it displays the output as shown below. the method next() is used when a file is used as an iterator, typically in a loop, the next() method is called repeatedly. this method returns the next input line, or raises stopiteration when eof is hit.

230.	What is the use of seek() method in files?
A.	sets the file’s current position at the offset
B.	sets the file’s previous position at the offset
C.	sets the file’s current position within the file
D.	none of the mentioned
Answer» A. sets the file’s current position at the offset
Explanation: sets the file’s current position at the offset. the method seek() sets the file’s current position at the offset.

231.	What is the use of truncate() method in file?
A.	truncates the file size
B.	deletes the content of the file
C.	deletes the file size
D.	none of the mentioned
Answer» A. truncates the file size
Explanation: the method truncate() truncates the file size. following is the syntax for truncate() method:

232.	Which is/are the basic I/O connections in file?
A.	standard input
B.	standard output
C.	standard errors
D.	all of the mentioned
Answer» D. all of the mentioned
Explanation: standard input, standard output and standard error. standard input is the data that goes to the program. the standard input comes from a keyboard. standard output is where we print our data with the print keyword. unless redirected, it is the terminal console. the standard error is a stream where programs write their error messages. it is usually the text terminal.

233.	sys.stdout.write('Python\n')
A.	compilation error
B.	runtime error
C.	hello python
D.	hello python
Answer» D. hello python
Explanation: none output:

234.	What is the pickling?
A.	it is used for object serialization
B.	it is used for object deserialization
C.	none of the mentioned
D.	all of the mentioned
Answer» A. it is used for object serialization
Explanation: pickle is the standard mechanism for object serialization. pickle uses a simple stack-based virtual machine that records the instructions used to reconstruct the object. this makes pickle vulnerable to security risks by malformed or maliciously constructed data, that may cause the deserializer to import arbitrary modules and instantiate any object.

235.	What is unpickling?
A.	it is used for object serialization
B.	it is used for object deserialization
C.	none of the mentioned
D.	all of the mentioned
Answer» B. it is used for object deserialization
Explanation: we have been working with simple textual data. what if we are working with objects rather than simple text? for such situations, we can use the pickle module. this module serializes python objects. the python objects are converted into byte streams and written to text files. this process is called pickling. the inverse operation, reading from a file and reconstructing objects is called deserializing or unpickling.