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Solutions for Computer Science, Class 11, CBSE
Boolean data type is internally treated as integer data type.
Two forms of floating-point numbers are: fractional form and exponent notation.
Python's floating point numbers have precision of 15 digits.
Three mutable types of Python are lists, dictionaries and sets.
The floor division of two integers yields a result of integer type.
The division of two integers yields a result of floating-point type.
The set sequence type cannot store duplicate values.
The tuple datatype is like lists but is not mutable.
The id of an object gives the memory location of the object.
To check if two objects reference the same memory address, is operator is used.
To use function fabs( ), math module should be imported.
To generate a random floating number in the range 0 to 100, random() or random.random() function is used.
To generate a random integer in a range, randint() or random.randint() function is used.
To generate a random number in a sequence of values where two values have a difference a step value, randrange() or random.randrange() function is used.
To use mean() function, statistics module is to be imported.
Which of the following are valid Python data types ?
Which of the following are datatypes considered as Numbers in Python.
Consider the following sequence of statements:
a = 35
m = a
Following the execution of these statements, Python has created how many objects and how many references ?
Which Python built-in function returns the unique number assigned to an object?
The operator used to check if both the operands reference the same object memory, is the .......... operator.
For two objects x and y, the expression x is y will yield True, if and only if
Which of the following is not an immutable type in Python ?
Python operator always yields the result of .......... datatype.
What is the value of the expression 100 / 25 ?
What is the value of the expression 100 // 25 ?
In Python, a variable must be declared before it is assigned a value.
In Python, a variable is assigned a value of one type, and then later assigned a value of a different type. This will yield .......... .
In Python, a variable may be assigned a value of one type, and then later assigned a value of a different type. This concept is known as .......... .
Is it safe to directly use the == operator to determine whether objects of type float are equal ?
What will the following code produce ?
a = 8.6
b = 2
print ( a//b )
In the Python statement x = a + 5 - b : a and b are .......... .
In the Python statement x =a + 5 - b : a + 5 - b is .......... .
What will be the value of y after following code fragment is executed ?
x = 10.0
y = (x < 100.0) and x >= 10
Which of the following literals has True truth-value ?
What will the following code result as ?
import math
x = 100
print ( x > 0 and math.sqrt( x ) )
Which of the following operators has the lowest precedence ?
What is the value of the expression 10 + 3 ** 3 * 2?
To increase the value of x five times using an augmented assignment operator, the correct expression will be
What will be the result of the expression 10 or 0 ?
What will be the result of the expression 5 or 10 ?
What will be the result of the expression 5 and 10?
What will be the result of the expression 15 and 10?
What will be the result of the expression 10 or 0 ?
What will be the result of the expression 'a' or " (" is an empty string) ?
What will be the result of the expression 'a' and " (" is an empty string) ?
What will be the result of the expression 'x' and 'a' ?
What will be the result of the expression 'a' and 'x' ?
What will be the result of the expression 'a' and 'None' ?
What will be the result of the expression 'None' and 'a' ?
What will be the result of the expression 'false' and False ?
What will be the result of the expression 'false' or False ?
List is an immutable data type.
False
Set is a mutable data type.
True
A set can contain duplicate values in it.
False
A Boolean value is internally treated as an integer value.
True
'' (an empty string) has truth value as False.
True
' ' (a space) has truth value as False.
False
Value false is a legal literal value in Python.
False
Value False is a legal literal value in Python.
True
Value 'False' is a legal literal value in Python.
True
Value 'false' is a legal literal value in Python.
True
None and 'None' are the same.
False
None has the truth value as False.
True
'None' has the truth value as False.
False
The result of bool(0) is False.
True
The result of bool('None') is False.
False
Dividing two integers results in an integer.
False
Floor division of two integers results in an integer.
True
Two floating point numbers should not be compared for equality using ==
True
In implicit conversion, all operands' data types are converted to the datatype of the largest operand.
True
Explicit type conversion involves the use of a function to convert datatype of a value.
True
What are data types in Python? How are they important?
Answer
Data types are used to identify the type of data a memory location can hold and the associated operations of handling it. The data that we deal with in our programs can be of many types like character, integer, real number, string, boolean, etc. hence programming languages including Python provide ways and facilities to handle all these different types of data through data types. The data types define the capabilities to handle a specific type of data such as memory space it allocates to hold a certain type of data and the range of values supported for a given data type, etc.
How many integer types are supported by Python? Name them.
Answer
Two integer types are supported by Python. They are:
How are these numbers different from one another (with respect to Python)? 33, 33.0, 33j, 33 + j
Answer
The number 33 is an integer whereas 33.0 is a floating-point number. 33j represent the imaginary part of a complex number. 33 + j is a complex number.
The complex numbers have two parts : real and imaginary. In which data type are real and imaginary parts represented ?
Answer
In Python, the real and imaginary parts of a complex number are represented as floating-point numbers.
How many string types does Python support? How are they different from one another?
Answer
Python supports two types of strings — Single-line strings and Multi-line strings. Single line strings are enclosed in single or double quotes and terminate in one line. Multi-line strings store multiple lines of text and are enclosed in triple quotes.
What will following code print?
str1 = '''Hell
o'''
str2 = '''Hell\
o'''
print(len(str1) > len(str2))
Answer
This code will print:
True
len(str1) is 6 due to the EOL character. len(str2) is 5 as backslash (\) character is not counted in the length of string. As len(str1) is greater than len(str2) so the output is True.
What are Immutable and Mutable types in Python? List immutable and mutable types of Python.
Answer
Mutable types are those whose values can be changed in place whereas Immutable types are those that can never change their value in place.
Mutable types in Python are:
Immutable types in Python are:
What are three internal key-attributes of a value-variable in Python ? Explain with example.
Answer
The three internal key-attributes of a value-variable in Python are:
For example, consider this:
a = 4
The type of a is int which can be found with the built-in function type() like this:
type(a).
Value can be found using the built-in function print() like this:
print(a)
It will give the output as 4 which is value contained in variable a.
Id is the memory location of the object which can be determined using built-in function id() like this:
id(a)
Is it true that if two objects return True for is operator, they will also return True for == operator?
Answer
Yes, if is operator returns true, it implicitly means that the equality operator will also return True. is operator returning true implies that both the variables point to the same object and hence == operator must return True.
Are these values equal? Why/why not?
Answer
What is an atom in Python? What is an expression?
Answer
In Python, an atom is something that has a value. Identifiers, literals, strings, lists, tuples, sets, dictionaries, etc. are all atoms. An expression in Python, is any valid combination of operators and atoms. It is composed of one or more operations.
What is the difference between implicit type conversion and explicit type conversion?
Answer
Implicit Type Conversion | Explicit Type Conversion |
---|---|
An implicit type conversion is automatically performed by the compiler when differing data types are intermixed in an expression. | An explicit type conversion is user-defined conversion that forces an expression to be of specific type. |
An implicit type conversion is performed without programmer's intervention. | An explicit type conversion is specified explicitly by the programmer. |
Example: a, b = 5, 25.5 c = a + b | Example: a, b = 5, 25.5 c = int(a + b) |
Two objects (say a and b) when compared using == ,return True. But Python gives False when compared using is operator. Why? (i.e., a == b is True but why is a is b False?)
Answer
As equality (==) operator returns True, it means that a and b have the same value but as is operator returns False, it means that variables a and b point to different objects in memory. For example, consider the below Python statements:
>>> a = 'abc'
>>> b = input("Enter a string: ")
Enter a string: abc
>>> a == b
True
>>> a is b
False
Here, both a and b have the same value 'abc' but they point to different objects.
Given str1 = "Hello", what will be the values of:
(a) str1[0]
(b) str1[1]
(c) str1[-5]
(d) str1[-4]
(e) str1[5]
Answer
(a) H
(b) e
(c) H
(d) e
(e) IndexError: string index out of range
If you give the following for str1 = "Hello", why does Python report error?
str1[2] = 'p'
Answer
Python reports error because strings are immutable and hence item assignment is not supported.
What will the result given by the following?
(a) type (6 + 3)
(b) type (6 -3)
(c) type (6 *3)
(d) type (6 / 3)
(e) type (6 // 3)
(f) type (6 % 3)
Answer
(a) type (6 + 3)
⇒ int + int
⇒ int
So the result is int.
(b) type (6 -3)
⇒ int - int
⇒ int
So the result is int.
(c) type (6 * 3)
⇒ int * int
⇒ int
So the result is int.
(d) type (6 / 3)
⇒ int / int
⇒ float
So the result is float.
(e) type (6 // 3)
⇒ int // int
⇒ int
So the result is int.
(f) type (6 % 3)
⇒ int % int
⇒ int
So the result is int.
What are augmented assignment operators? How are they useful?
Answer
Augmented assignment operators combine the impact of an arithmetic operator with an assignment operator. For example, to add the value of b to the value of a and assign the result back to a then instead of writing:
a = a + b
we can write
a += b.
Augmented assignment operators are useful as they provide a shorthand way by combining the arithmetic and assignment operators.
Differentiate between (555/222)**2 and (555.0/222)**2.
Answer
In the first expression, 555 is of int type whereas in the second expression 555.0 is of float type.
Given three Boolean variables a, b, c as : a = False, b = True, c = False. Evaluate the following Boolean expressions:
(a) b and c
(b) b or c
(c) not a and b
(d) (a and b) or not c
(e) not b and not (a or c)
(f) not ((not b or not a) and c) or a
Answer
(a) b and c
⇒ False and True
⇒ False
(b) b or c
⇒ True or False
⇒ True
(c) not a and b
⇒ not False and True
⇒ True and True
⇒ True
(d) (a and b) or not c
⇒ (False and True) or not False
⇒ False or not False
⇒ False or True
⇒ True
(e) not b and not (a or c)
⇒ not True and not (False or False)
⇒ not True and not False
⇒ False and True
⇒ False
(f) not ((not b or not a) and c) or a
⇒ not ((not True or not False) and False) or False
⇒ not ((False or True) and False) or False
⇒ not (True and False) or False
⇒ not False or False
⇒ True or False
⇒ True
What would following code fragments result in? Given x = 3.
(a) 1 < x
(b) x >= 4
(c) x == 3
(d) x == 3.0
(e) "Hello" == "Hello"
(f) "Hello" > "hello"
(g) 4/2 == 2.0
(h) 4/2 == 2
(i) x < 7 and 4 > 5.
Answer
(a) True
(b) False
(c) True
(d) True
(e) True
(f) False
(g) True
(h) True
(i) False
Write following expressions in Python:
(a)
Answer
1 / 3 * b * b * h
(b)
Answer
math.pi * r * r * h
(c)
Answer
1 / 3 * math.pi * r * r * h
(d)
Answer
math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
(e)
Answer
(x - h) ** 2 + (y - k) ** 2 == r ** 2
(f)
Answer
x = (-b + math.sqrt(b * b - 4 * a * c)) / (2 * a)
(g)
Answer
a ** n * a ** m == a ** (n + m)
(h)
Answer
(a ** n) ** m == a ** (n * m)
(i)
Answer
a ** n / a ** m == a ** (n - m)
(j)
Answer
a ** -n == 1 / a ** n
int('a') produces error. Why ?
Answer
int() converts its argument into an integer. As 'a' is a letter, it cannot be converted into a valid integer hence int('a') produces an error.
int('a') produces error but following expression having int('a') in it, does not return error. Why?
len('a') + 2 or int('a')
Answer
The or operator tests the second operand only if the first operand is false otherwise it ignores it. In the expression, the first operand of or operator is len('a') + 2. It evaluates to 3 and as it is a non-zero value hence it is True for or operator. As first operand of or operator is True so it doesn't evaluate its second argument int('a') and no error is returned.
Write expression to convert the values 17, len('ab') to (i) integer (ii) str (iii) boolean values
Answer
(i) int(17), int(len('ab'))
(ii) str(17), str(len('ab'))
(iii) bool(17), bool(len('ab'))
Evaluate and Justify:
(i) 22 / 17 = 37 / 47 + 88 /83
(ii) len('375')**2
Answer
(i) It produces an error as LHS value in this case is an expression that evaluates to a literal whereas LHS value should be a variable.
(ii) len('375')**2
⇒ 3 ** 2 [∵ len('375') = 3]
⇒ 9 [∵ 3 * 3 = 9]
Evaluate and Justify:
(i) 22.0/7.0 - 22/7
(ii) 22.0/7.0 - int(22.0/7.0)
(iii) 22/7 - int (22.0)/7
Answer
(i) 22.0/7.0 - 22/7
⇒ 0
As values of 22.0/7.0 and 22/7 are equal, subtracting them will give the result as 0.0.
(ii) 22.0/7.0 - int(22.0/7.0)
⇒ 3.142857142857143 - 3
⇒ 0.142857142857143
(iii) 22/7 - int (22.0)/7
⇒ 0.0
int (22.0) gives 22 so the expression becomes 22/7 - 22/7 which results in 0.0
Evaluate and Justify:
(i) false and None
(ii) 0 and None
(iii) True and None
(iv) None and None
Answer
(i) This produces an error as false is an invalid literal in Python. It should be False. Had the expression being False and None, the return value will be False.
(ii) This logical expression evaluates to 0. As first operand of and operator is false so it will return the first operand itself.
(iii) This logical expression evaluates to None. As first operand of and operator is True so it will return the second operand.
(iv) This logical expression evaluates to None. As first operand of and operator is false so it will return the first operand itself.
Evaluate and Justify:
(a) 0 or None and "or"
(b) 1 or None and 'a' or 'b'
(c) False and 23
(d) 23 and False
(e) not (1 == 1 and 0 != 1)
(f) "abc" == "Abc" and not (2 == 3 or 3 == 4)
(g) False and 1 == 1 or not True or 1 == 1 and False or 0 == 0
Answer
(a) 0 or None and "or"
⇒ 0 or None [∵ and has higher precedence than or]
⇒ None
(b) 1 or None and 'a' or 'b'
⇒ 1 or None or 'b'
⇒ 1 or 'b'
⇒ 1
(c) False and 23
⇒ False
(d) 23 and False
⇒ False
(e) not (1 == 1 and 0 != 1)
⇒ not (True and True)
⇒ not True
⇒ False
(f) "abc" == "Abc" and not (2 == 3 or 3 == 4)
⇒ "abc" == "Abc" and not (False or False)
⇒ "abc" == "Abc" and not False
⇒ False and not False
⇒ False and True
⇒ False
(g) False and 1 == 1 or not True or 1 == 1 and False or 0 == 0
⇒ False and True or not True or True and False or True
⇒ False and True or False or True and False or True
⇒ False or False or False or True
⇒ False or False or True
⇒ False or True
⇒ True
Evaluate the following for each expression that is successfully evaluated, determine its value and type for unsuccessful expression, state the reason.
(a) len("hello") == 25/5 or 20/10
(b) 3 < 5 or 50/(5 - (3 + 2))
(c) 50/(5 - (3 + 2)) or 3 < 5
(d) 2 * (2 * (len("01")))
Answer
(a) len("hello") == 25/5 or 20/10
⇒ 5 == 25/5 or 20/10
⇒ 5 == 5 or 2
⇒ True or 2
⇒ True
The type of result is Boolean.
(b) 3 < 5 or 50/(5 - (3 + 2))
⇒ True or 50/(5 - (3 + 2)) [∵ first operand is True, second operand is not evaluated so no division by 0 error happens]
⇒ True
The type of result is Boolean.
(c) 50/(5 - (3 + 2)) or 3 < 5
⇒ 50/(5 - 5) or 3 < 5
⇒ 50/0 or 3 < 5
⇒ Division by Zero Error
As the denominator of or operator's first operand is 0, Division by Zero error occurs.
(d) 2 * (2 * (len("01")))
⇒ 2 * (2 * 2)
⇒ 2 * 4
⇒ 8
The type of result is Integer.
Write an expression that uses exactly 3 arithmetic operators with integer literals and produces result as 99.
Answer
9 * 10 + 21 % 12
Add parentheses to the following expression to make the order of evaluation more clear.
y % 4 == 0 and y % 100 != 0 or y % 400 == 0
Answer
((y % 4) == 0) and ((y % 100) != 0) or ((y % 400) == 0)
A program runs to completion but gives an incorrect result. What type of error would have caused it?
Answer
Logical errors can make a program run till completion but give incorrect result.
In Python, strings are immutable while lists are mutable. What is the difference?
Answer
In Python, strings are immutable means that individual letter assignment for strings is not allowed. For example:
name='hello'
name[0] = 'p'
The above Python code will cause an error as we are trying to assign some value to an individual letter of a string.
Lists are mutable in Python means that we can assign values to individual elements of a list. For example:
a = [1, 2, 3, 4, 5]
a[0] = 10
The above Python code will work correctly without any errors as Lists are mutable in Python.
How does the // operator differ from the / operator? Give an example of where // would be needed.
Answer
The Division operator (/) divides its first operand by second operand and always returns the result as a float value whereas Floor Division operator (//) divides its first operand by second operand and truncates the fractional part of the result and returns it as an int value. Floor Division operator is useful in situations where we only need the integer part of the division operation result. For example, to determine how many minutes are there in some given number of seconds:
secs = 2565
mins = 2565 // 60
MidAir Airlines will only allow carry-on bags that are no more than 22 inches long, 14 inches wide, and 9 inches deep. Assuming that variables named length, width, and depth have already been assigned values, write an expression combining the three that evaluates to True if bag fits within those limits, and False otherwise.
Answer
length <= 22 and width <= 14 and depth <= 9
What are main error types? Which types are most dangerous and why?
Answer
The types of errors are:
Logical Errors are the most dangerous as they are hardest to prevent, find and fix.
Correct any false statements:
(a) Compile-time errors are usually easier to detect and to correct than run-time errors.
(b) Logically errors can usually be detected by the compiler.
Answer
(a) The statement is correct.
(b) The statement is incorrect. The correct statement should be:
Logical errors cannot be detected by the compiler.
Differentiate between a syntax error and a semantics error.
Answer
Syntax Error | Semantics Error |
---|---|
Syntax errors occurs when the rules of the programming language are violated. | Semantic errors occur when the statement are not meaningful. |
Example: x = false | Example: x * y = z |
Differentiate between a syntax error and a logical error in a python program. When is each type of error likely to be found?
Answer
Syntax Error | Logical Error |
---|---|
Syntax Errors occur when we violate the rules of writing the statements of the programming language. | Logical Errors occur due to our mistakes in programming logic. |
Program fails to compile and execute. | Program compiles and executes but doesn't give the desired output. |
Syntax Errors are caught by the compiler. | Logical errors need to be found and corrected by people working on the program. |
Syntax errors are found at compile type whereas Logical errors are found when the program starts executing.
What is the difference between an error and exception?
Answer
An Error is a bug in the code that causes irregular output or stops the program from executing whereas an Exception is an irregular unexpected situation occurring during execution on which programmer has no control.
What is the result produced by (i) bool (0) (ii) bool (str(0))? Justify the outcome.
Answer
(i) bool (0)
The result is False as truth value of 0 is falsetval
(ii) bool (str(0))
The result is True as str(0) converts 0 to string "0". As it becomes a non-empty string so its truth value is truetval
What will be the output, if input for both the statements is 5 + 4/2.
6 == input ("Value 1:")
6 == int(input ("value 2:"))
Answer
Output of first statement is False as '5 + 4/2' is entered as a string so it cannot be equal to the number 6.
The second statement gives an error as int() function cannot convert the string '5 + 4/2' to a valid integer.
Following Python code has an expression with all integer values. Why is the result in floating point form?
a, b, c = 2, 3, 6
d = a + b * c/b
print(d)
Answer
The output of the above Python code is 8.0. Division operator is present in the expression. The result of Division operator is of float type. Due to implicit conversion, other operand in this expression are also converted to float type and hence the final result is in floating point form.
What will following code print?
a = va = 3
b = va = 3
print (a, b)
Answer
This Python code prints:
3 3
What will following code print?
a = 3
b = 3.0
print (a == b)
print (a is b)
Answer
This Python code prints:
True
False
As values of a and b are equal so equality operator returns True. a is of int type and b is of float type so a and b are different objects so a is b returns False.
What will be output produced by following code? State reason for this output.
a, b, c = 1, 1, 2
d = a + b
e = 1.0
f = 1.0
g = 2.0
h = e + f
print(c == d)
print(c is d)
print(g == h)
print(g is h)
Answer
True
True
True
False
Value of d becomes 2 and as values of c and d are equal so print(c == d) prints True.
What will be output produced by following code? State reason for this output.
a = 5 - 4 - 3
b = 3**2**3
print(a)
print(b)
Answer
-2
6561
a = 5 - 4 - 3
⇒ a = 1 - 3
⇒ a = -2
The exponentiation operator (**) has associativity from right to left so:
b = 3**2**3
⇒ b = 3**8
⇒ b = 6561
What will be output produced by following code? State reason for this output.
a, b, c = 1, 1, 1
d = 0.3
e=a+b+c-d
f=a+b+c == d
print(e)
print(f)
Answer
2.7
False
e = a+b+c-d
⇒ e = 1+1+1-0.3
⇒ e = 3-0.3
⇒ e = 2.7
As 0.3 is float so implicit conversion converts 3 also to float and result of the expression is of float type.
f = a + b + c == d
⇒ f = 1 + 1 + 1 == 0.3
⇒ f = 3 == 0.3
⇒ f = False
What will be the output of following Python code?
a = 12
b = 7.4
c = 1
a -= b
print(a, b)
a *= 2 + c
print(a)
b += a * c
print(b)
Answer
4.6 7.4
13.799999999999999
21.2
a -= b
⇒ a = a - b
⇒ a = 12 - 7.4
⇒ a = 4.6
a *= 2 + c
⇒ a = 4.6 * (2 + c)
⇒ a = 4.6 * (2 + 1)
⇒ a = 4.6 * 3
⇒ a = 13.799999999999999
b += a * c
⇒ b = b + (a * c)
⇒ b = 7.4 + (13.799999999999999 * 1)
⇒ b = 7.4 + 13.799999999999999
⇒ b = 21.2
What will be the output of following Python code?
x, y = 4, 8
z = x/y*y
print(z)
Answer
4.0
z = x/y*y
⇒ z = 4/8*8
⇒ z = 0.5*8
⇒ z = 4.0
Make change in the expression for z of previous question so that the output produced is zero. You cannot change the operators and order of variables. (Hint. Use a function around a sub-expression)
Answer
x, y = 4, 8
z = int(x/y)*y
print(z)
Consider the following expression:
x = "and" * (3 + 2) > "or" + "4"
What is the data type of value that is computed by this expression?
Answer
The data type of value that is computed by this expression is bool.
x = "and" * (3 + 2) > "or" + "4"
⇒ x = "and" * 5 > "or" + "4"
⇒ x = "andandandandand" > "or4"
⇒ x = False
Consider the following code segment:
a = input()
b = int(input())
c = a + b
print(c)
When the program is run, the user first enters 10 and then 5, it gives an error. Find the error, its reason and correct it
Answer
The error is:
TypeError: can only concatenate str (not "int") to str
It occurs because a is of type string but b is of type int. We are trying to add together a string operand and an int operand using addition operator. This is not allowed in Python hence this error occurs.
To correct it, we need to cast a to int like this:
a = int(input())
Consider the following code segment:
a = input("Enter the value of a:")
b = input("Enter the value of b:")
print(a + b)
If the user runs the program and enters 11 for a and 9 for b then what will the above code display?
Answer
Enter the value of a:11
Enter the value of b:9
119
input() function accepts user input as string type. The data type of a and b is string not int so addition operator concatenates them to print 119 instead of 20.
Find out the error and the reason for the error in the following code. Also, give the corrected code.
a, b = "5.0", "10.0"
x = float(a/b)
print(x)
Answer
a and b are defined as strings not float or int. Division operator doesn't support strings as its operand so we get the error — unsupported operand type(s) for /: "str" and "str".
The corrected code is:
a, b = 5.0, 10.0
x = float(a/b)
print(x)
Consider the following program. It is supposed to compute the hypotenuse of a right triangle after the user enters the lengths of the other two sides.
a = float(input("Enter the length of the first side:"))
b = float(input("Enter the length of the second side:"))
h = sqrt(a * a + b * b)
print("The length of the hypotenuse is", h)
When this program is run, the following output is generated (note that input entered by the user is shown in bold):
Enter the length of the first side: 3
Enter the length of the second side: 4
Traceback (most recent call last):
h = sqrt(a * a + b * b)
NameError: name 'sqrt' is not defined
Why is this error occurring? How would you resolve it ?
Answer
The error is coming because math module is not imported in the code. To resolve it, we should import the math module using the import statement import math.
Consider the following program. It is supposed to compute the hypotenuse of a right triangle after the user enters the lengths of the other two sides.
a = float(input("Enter the length of the first side:"))
b = float(input("Enter the length of the second side:"))
h = sqrt(a * a + b * b)
print("The length of the hypotenuse is", h)
After adding import math to the code given above, what other change(s) are required in the code to make it fully work ?
Answer
After adding import math statement, we need to change the line h = sqrt(a * a + b * b)
to h = math.sqrt(a * a + b * b)
. The corrected working code is below:
import math
a = float(input("Enter the length of the first side:"))
b = float(input("Enter the length of the second side:"))
h = math.sqrt(a * a + b * b)
print("The length of the hypotenuse is", h)
Which of the following expressions will result in an error message being displayed when a program containing it is run?
(a) 2.0/4
(b) "3" + "Hello"
(c) 4 % 15
(d) int("5")/float("3")
(e) float("6"/"2")
Answer
(a) No Error
(b) No Error
(c) No Error
(d) No Error
(e) This will cause an error of unsupported operand types as using division operator on string types is not allowed in Python.
Following expression does not report an error even if it has a sub-expression with 'divide by zero' problem:
3 or 10/0
What changes can you make to above expression so that Python reports this error?
Answer
Interchanging the operands of or operator as shown below will make Python report this error:
10/0 or 3
What is the output produced by following code?
a, b = bool(0), bool(0.0)
c, d = str(0), str(0.0)
print (len(a), len(b))
print (len(c), len(d))
Answer
The above code will give an error as the line print (len(a), len(b))
is calling len function with bool arguments which is not allowed in Python.
Given a string s = "12345". Can you write an expression that gives sum of all the digits shown inside the string s i.e., the program should be able to produce the result as 15 (1+2+3+4+5).
[Hint. Use indexes and convert to integer]
Answer
print(int(s[0]) + int(s[1]) + int(s[2]) + int(s[3]) + int(s[4]))
Predict the output if e is given input as 'True':
a = True
b = 0 < 5
print (a == b)
print (a is b)
c = str (a)
d = str (b)
print (c == d)
print (c is d)
e = input ("Enter :")
print (c == e)
print (c is e)
Answer
True
True
True
True
Enter :True
True
False
print (a == b)
gives True as a and b both are True.print (a is b)
gives True as a and b both being True point to the same object in memory.print (c == d)
and print (c is d)
give True as c and d both are string and point to the same object in memory.print (c == e)
gives True.print (c is e)
gives False.Find the errors(s)
name = "HariT"
print (name)
name[2] = 'R'
print (name)
Answer
The line name[2] = 'R'
is trying to assign the letter 'R' to the second index of string name but strings are immutable in Python and hence such item assignment for strings is not supported in Python.
Find the errors(s)
a = bool (0)
b = bool (1)
print (a == false)
print (b == true)
Answer
false and true are invalid literals in Python. The correct boolean literals are False and True.
Find the errors(s)
print (type (int("123")))
print (type (int("Hello")))
print (type (str("123.0")))
Answer
In the line print (type (int("Hello")))
, string "Hello" is given as an argument to int() but it cannot be converted into a valid integer so it causes an error.
Find the errors(s)
pi = 3.14
print (type (pi))
print (type ("3.14"))
print (type (float ("3.14")))
print (type (float("three point fourteen")))
Answer
In the line print (type (float("three point fourteen")))
, string "three point fourteen" is given as an argument to float() but it cannot be converted into a valid floating-point number so it causes an error.
Find the errors(s)
print ("Hello" + 2)
print ("Hello" + "2")
print ("Hello" * 2)
Answer
The line print ("Hello" + 2)
causes an error as addition operator (+) cannot concatenate a string and an int.
Find the errors(s)
print ("Hello"/2)
print ("Hello" / 2)
Answer
Both the lines of this Python code will give an error as strings cannot be used with division operator (/).
What will be the output produced?
x, y, z = True, False, False
a = x or (y and z)
b = (x or y) and z
print(a, b)
Answer
True False
What will be the output produced?
x, y = '5', 2
z = x + y
print(z)
Answer
This code produces an error in the line z = x + y
as operands of addition operator (+) are string and int, respectively which is not supported by Python.
What will be the output produced?
s = 'Sipo'
s1 = s + '2'
s2 = s * 2
print(s1)
print(s2)
Answer
Sipo2
SipoSipo
s1 = s + '2'
concatenates 'Sipo' and '2' storing 'Sipo2' in s1.s2 = s * 2
repeats 'Sipo' twice storing 'SipoSipo' in s2.What will be the output produced?
w, x, y, z = True , 4, -6, 2
result = -(x + z) < y or x ** z < 10
print(result)
Answer
False
-(x + z) < y or x ** z < 10
⇒ -(4 + 2) < -6 or 4 ** 2 < 10
⇒ -6 < -6 or 4 ** 2 < 10
⇒ -6 < -6 or 16 < 10
⇒ False or False
⇒ False
Program is giving a weird result of "0.50.50.50.50.50.50..........". Correct it so that it produces the correct result which is the probability value (input as 0.5) times 150.
probability = input("Type a number between 0 and 1: ")
print("Out of 150 tries, the odds are that only", (probability * 150), "will succeed.")
[Hint. Consider its datatype.]
Answer
The corrected program is below:
probability = float(input("Type a number between 0 and 1: "))
print("Out of 150 tries, the odds are that only", (probability * 150), "will succeed.")
Consider the code given below:
import random
r = random.randrange(100, 999, 5)
print(r, end = ' ')
r = random.randrange(100, 999, 5)
print(r, end = ' ')
r = random.randrange(100, 999, 5)
print(r)
Which of the following are the possible outcomes of the above code ? Also, what can be the maximum and minimum number generated by line 2 ?
(a) 655, 705, 220
(b) 380, 382, 505
(c) 100, 500, 999
(d) 345, 650, 110
Answer
The possible outcomes of the above code can be:
Option (a) — 655, 705, 220
Option (d) — 345, 650, 110
Maximum number can be 995 and minimum number can be 100.
Consider the code given below:
import random
r = random.randint(10, 100) - 10
print(r, end = ' ')
r = random.randint(10, 100) - 10
print(r, end = ' ')
r = random.randint(10, 100) - 10
print(r)
Which of the following are the possible outcomes of the above code? Also, what can be the maximum and minimum number generated by line 2?
(a) 12 45 22
(b) 100 80 84
(c) 101 12 43
(d) 100 12 10
Answer
The possible outcomes of the above code can be:
Option (a) — 12 45 22
Maximum number can be 90 and minimum number can be 0.
Consider the code given below:
import random
r = random.random() * 10
print(r, end = ' ')
r = random. random() * 10
print(r, end = ' ')
r = random.random() * 10
print(r)
Which of the following are the possible outcomes of the above code? Also, what can be the maximum and minimum number generated by line 2 ?
(a) 0.5 1.6 9.8
(b) 10.0 1.0 0.0
(c) 0.0 5.6 8.7
(d) 0.0 7.9 10.0
Answer
The possible outcomes of the above code can be:
Option (a) — 0.5 1.6 9.8
Option (c) — 0.0 5.6 8.7
Maximum number can be 9.999999..... and minimum number can be 0.
Consider the code given below:
import statistics as st
v = [7, 8, 8, 11, 7, 7]
m1 = st.mean(v)
m2 = st.mode(v)
m3 = st.median(v)
print(m1, m2, m3)
Which of the following is the correct output of the above code?
(a) 7 8 7.5
(b) 8 7 7
(c) 8 7 7.5
(c) 8.5 7 7.5
Answer
The correct output of the above code is:
Option (c) — 8 7 7.5
Write a program to obtain principal amount, rate of interest and time from user and compute simple interest.
p = float(input("Enter principal: "))
r = float(input("Enter rate: "))
t = float(input("Enter time: "))
si = p * r * t / 100
print("Simple Interest =", si)
Enter principal: 55000.75
Enter rate: 14.5
Enter time: 3
Simple Interest = 23925.32625
Write a program to obtain temperatures of 7 days (Monday, Tuesday ... Sunday) and then display average temperature of the week.
d1 = float(input("Enter Sunday Temperature: "))
d2 = float(input("Enter Monday Temperature: "))
d3 = float(input("Enter Tuesday Temperature: "))
d4 = float(input("Enter Wednesday Temperature: "))
d5 = float(input("Enter Thursday Temperature: "))
d6 = float(input("Enter Friday Temperature: "))
d7 = float(input("Enter Saturday Temperature: "))
avg = (d1 + d2 + d3 + d4 + d5 + d6 + d7) / 7
print("Average Temperature =", avg)
Enter Sunday Temperature: 21.6
Enter Monday Temperature: 22.3
Enter Tuesday Temperature: 24.5
Enter Wednesday Temperature: 23.0
Enter Thursday Temperature: 23.7
Enter Friday Temperature: 24.2
Enter Saturday Temperature: 25
Average Temperature = 23.47142857142857
Write a program to obtain x, y, z from user and calculate expression : 4x4 + 3y3 + 9z + 6π
import math
x = int(input("Enter x: "))
y = int(input("Enter y: "))
z = int(input("Enter z: "))
res = 4 * x ** 4 + 3 * y ** 3 + 9 * z + 6 * math.pi
print("Result =", res)
Enter x: 2
Enter y: 3
Enter z: 5
Result = 208.84955592153875
Write a program that reads a number of seconds and prints it in form : mins and seconds, e.g., 200 seconds are printed as 3 mins and 20 seconds.
[Hint. use // and % to get minutes and seconds]
totalSecs = int(input("Enter seconds: "))
mins = totalSecs // 60
secs = totalSecs % 60
print(mins, "minutes and", secs, "seconds")
Enter seconds: 200
3 minutes and 20 seconds
Write a program to take year as input and check if it is a leap year or not.
y = int(input("Enter year to check: "))
print(y % 4 and "Not a Leap Year" or "Leap Year")
Enter year to check: 2020
Leap Year
Write a program to take two numbers and print if the first number is fully divisible by second number or not.
x = int(input("Enter first number: "))
y = int(input("Enter second number: "))
print(x % y and "Not Fully Divisible" or "Fully Divisible")
Enter first number: 4
Enter second number: 2
Fully Divisible
Write a program to take a 2-digit number and then print the reversed number. That is, if the input given is 25, the program should print 52.
x = int(input("Enter a two digit number: "))
y = x % 10 * 10 + x // 10
print("Reversed Number:", y)
Enter a two digit number: 25
Reversed Number: 52
Try writing program (similar to previous one) for three digit number i.e., if you input 123, the program should print 321.
x = int(input("Enter a three digit number: "))
d1 = x % 10
x //= 10
d2 = x % 10
x //= 10
d3 = x % 10
y = d1 * 100 + d2 * 10 + d3
print("Reversed Number:", y)
Enter a three digit number: 123
Reversed Number: 321
Write a program to take two inputs for day, month and then calculate which day of the year, the given date is. For simplicity, take 30 days for all months. For example, if you give input as: Day3, Month2 then it should print "Day of the year : 33".
d = int(input("Enter day: "))
m = int(input("Enter month: "))
n = (m - 1) * 30 + d
print("Day of the year:", n)
Enter day: 3
Enter month: 2
Day of the year: 33
Write a program that asks a user for a number of years, and then prints out the number of days, hours, minutes, and seconds in that number of years.
How many years? 10
10.0 years is:
3650.0 days
87600.0 hours
5256000.0 minutes
315360000.0 seconds
y = float(input("How many years? "))
d = y * 365
h = d * 24
m = h * 60
s = m * 60
print(y, "years is:")
print(d, "days")
print(h, "hours")
print(m, "minutes")
print(s, "seconds")
How many years? 10
10.0 years is:
3650.0 days
87600.0 hours
5256000.0 minutes
315360000.0 seconds
Write a program that inputs an age and print age after 10 years as shown below:
What is your age? 17
In ten years, you will be 27 years old!
a = int(input("What is your age? "))
print("In ten years, you will be", a + 10, "years old!")
What is your age? 17
In ten years, you will be 27 years old!
Write a program whose three sample runs are shown below:
Sample Run 1:
Random number between 0 and 5 (A) : 2
Random number between 0 and 5 (B) :5.
A to the power B = 32
Sample Run 2:
Random number between 0 and 5 (A) : 4
Random number between 0 and 5 (B) :3.
A to the power B = 64
Sample Run 3:
Random number between 0 and 5 (A) : 1
Random number between 0 and 5 (B) :1.
A to the power B = 1
import random
a = random.randint(0, 5)
b = random.randint(0, 5)
c = a ** b
print("Random number between 0 and 5 (A) :", a)
print("Random number between 0 and 5 (B) :", b)
print("A to the power B =", c)
Random number between 0 and 5 (A) : 5
Random number between 0 and 5 (B) : 3
A to the power B = 125
Write a program that generates six random numbers in a sequence created with (start, stop, step). Then print the mean, median and mode of the generated numbers.
import random
import statistics
start = int(input("Enter start: "))
stop = int(input("Enter stop: "))
step = int(input("Enter step: "))
a = random.randrange(start, stop, step)
b = random.randrange(start, stop, step)
c = random.randrange(start, stop, step)
d = random.randrange(start, stop, step)
e = random.randrange(start, stop, step)
f = random.randrange(start, stop, step)
print("Generated Numbers:")
print(a, b, c, d, e, f)
seq = (a, b, c, d, e, f)
mean = statistics.mean(seq)
median = statistics.median(seq)
mode = statistics.mode(seq)
print("Mean =", mean)
print("Median =", median)
print("Mode =", mode)
Enter start: 100
Enter stop: 500
Enter step: 5
Generated Numbers:
235 255 320 475 170 325
Mean = 296.6666666666667
Median = 287.5
Mode = 235
Write a program to generate 3 random integers between 100 and 999 which is divisible by 5.
import random
a = random.randrange(100, 999, 5)
b = random.randrange(100, 999, 5)
c = random.randrange(100, 999, 5)
print("Generated Numbers:", a, b, c)
Generated Numbers: 885 825 355
Write a program to generate 6 digit random secure OTP between 100000 to 999999.
import random
otp = random.randint(100000, 999999);
print("OTP:", otp);
OTP: 553072
Write a program to generate 6 random numbers and then print their mean, median and mode.
import random
import statistics
a = random.random()
b = random.random()
c = random.random()
d = random.random()
e = random.random()
f = random.random()
print("Generated Numbers:")
print(a, b, c, d, e, f)
seq = (a, b, c, d, e, f)
mean = statistics.mean(seq)
median = statistics.median(seq)
mode = statistics.mode(seq)
print("Mean =", mean)
print("Median =", median)
print("Mode =", mode)
Generated Numbers:
0.47950245404109626 0.6908539320958872 0.12445888663826654 0.13613724999684718 0.37709141355821396 0.6369609321575742
Mean = 0.40750081141464756
Median = 0.4282969337996551
Mode = 0.47950245404109626
Write a program to find a side of a right angled triangle whose two sides and an angle is given.
import math
a = float(input("Enter base: "))
b = float(input("Enter height: "))
x = float(input("Enter angle: "))
c = math.sqrt(a ** 2 + b ** 2)
print("Hypotenuse =", c)
Enter base: 10.5
Enter height: 5.5
Enter angle: 60
Hypotenuse = 11.853269591129697
Write a program to calculate the radius of a sphere whose area (4πr2) is given.
import math
area = float(input("Enter area of sphere: "))
r = math.sqrt(area / (4 * math.pi))
print("Radius of sphere =", r)
Enter area of sphere: 380.14
Radius of sphere = 5.50005273006328
Write a program that inputs a string and then prints it equal to number of times its length, e.g.,
Enter string : "eka"
Result ekaekaeka
str = input("Enter string: ")
len = len(str)
opStr = str * len
print("Result", opStr)
Enter string: eka
Result ekaekaeka
Find the volume of the cylinder (πr2h) as shown:
Radius = 8 cm
Height = 15 cm
import math
r = 8
h = 15
v = math.pi * r * r * h
print("Volume of Cylinder =", v)
Volume of Cylinder = 3015.928947446201
Write a program to calculate the area of an equilateral triangle. (area = (√3 / 4) * side * side).
import math
side = float(input("Enter side: "))
area = math.sqrt(3) / 4 * side * side
print("Area of triangle =", area)
Enter side: 5
Area of triangle = 10.825317547305481
Write a program to input the radius of a sphere and calculate its volume (V = 4/3πr3)
import math
r = float(input("Enter radius of sphere: "))
v = 4 / 3 * math.pi * r ** 3
print("Volume of sphere = ", v)
Enter radius of sphere: 3.5
Volume of sphere = 179.59438003021648
Write a program to calculate amount payable after simple interest.
p = float(input("Enter principal: "))
r = float(input("Enter rate: "))
t = float(input("Enter time: "))
si = p * r * t / 100
amt = p + si
print("Amount Payable =", amt)
Enter principal: 55000.75
Enter rate: 14.5
Enter time: 3
Amount Payable = 78926.07625
Write a program to calculate amount payable after compound interest.
p = float(input("Enter principal: "))
r = float(input("Enter rate: "))
t = float(input("Enter time: "))
amt = p * (1 + r / 100) ** t
print("Amount Payable =", amt)
Enter principal: 15217.75
Enter rate: 9.2
Enter time: 3
Amount Payable = 19816.107987312007
Write a program to compute (a + b)3 using the formula a3 + b3 + 3a2b + 3ab2
a = int(input("Enter a: "))
b = int(input("Enter b: "))
res = a ** 3 + b ** 3 + 3 * a ** 2 * b + 3 * a * b ** 2
print("Result =", res)
Enter a: 3
Enter b: 5
Result = 512