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P.I.P: - 7.1

 

 

Q1. Consider the following code: what is the value of ‘a’ at the end?

 

a = [1, 2, 3]

a [2] = 0

a [a [ 2 ] ] = 5

a [1:2] = []

 

Answer =

 

Value of ‘a’ at the end is:

[5, 0]

 

 

 

 

 

 

 

Q2. You have a list a = [1, 2, [3, 4], 5]. Now answer the following. Verify your answers in Python Shell.

 

(a)	What is the length of a?	4
(b)	How many elements does it contain? What are their types?	It contain 4 element. 3 integer type & 1 list.
(c)	How many integers?	3 integer
(d)	What does len(a[2]) return?	2
(e)	What does a[len(a)] evaluate to?	It give error.
(f)	What does a [-1 * len(a)] evaluate to?	Output:- 1

 

 

 

 

 

 

 

Q4. Given a list List1 = [1, 2, 3].

 

Run the following two statements for the list List1 and explain how these two statements are different:

 

List1 += 4 # statement

List1 += [4] # statement

 

Explanation

 

Answer =

 

Because in statement 1 there is addition of list and integer which is not possible. While in statement 2 there is addition of two lists which is possible.

 

 

 

 

 

 

 

P.I.P: - 7.2

 

 

Q4. Write a program that returns the largest even number in the list of integers. If there is no even number in the input, print "No even element".

 

Examples:

With list[3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 9] it will print 6

With list(3, -1001] it will print "No even element" 20

With list[ 6, 18, 23, 20, 29] it will print 20

 

Write the program code.

 

Answer =

 

lst = eval (input("Enter the number list :- "))

newlst = []

for i in lst :

    if i % 2 == 0 :

        newlst += [ i ]

if newlst == [] :

    print ("No even element")

else :

    newlst.sort()

    print ("largest even number in the list is :- ", newlst[-1])

       

 

 

 

 

 

Q5. Write a program that prints the sum of the even-indexed elements of L, minus the sum of the odd-indexed elements of L.

 

For example:

For list[1, 2, 3, 4, 5, 6] it should print -3 (that is, (1 + 3 + 5) - (2 + 4 + 6))

For list([1, 2, 3]) it should print 2 (that is, 1 - 2 + 3)

 

Answer =

 

L = eval (input("Enter the number list :- "))

even = odd = 0

for i in range (len(L)) :

    if i % 2 == 0 :

        even += L[ i ]

    else :

        odd += L[ i ]

print ("(sum of even-indexed elements) - (sum of odd-indexed elements) :-", even - odd)

       

 

 

 

 

Q6. Given a list of strings L, write a program below that prints a single string containing all of the elements of L concatenated (joined) together with a hyphen in between two elements.

 

Answer =

 

lst = eval (input("Enter a List :-"))

string = ""

for i in range (len(lst)) :

    if i == len(lst) - 1 :

        string += lst[i]

    else :

        string = string + lst[ i ] + "-"

print ("New word is :- ", string)

 

 

 

 

 

 

Q7. Predict the output:-

 

(a)

lst = [1, 2, 3]

myvar = lst[0]

lst[0] = 18

print (lst)

print (myvar)

 

(b)

myvar = 18

lst = [myvar, 2, 3]

myvar = 22

print (lst)

print (myvar)

 

(c)

a = [1, 2, [3, 4], 5]

print(len(a))

print(-1 * len(a))

print(a[2], len(a[2]))

 

(d)

a = [1, 2, 3]

a[2]=0

a[a[2]] = 5

a[1:2] = []

print(a)

 

(e)

a = [ 55, 44, 33, 22, 11, 0]

print(a[0] )

print(a[-1] )

print(a[a[0]] )

print( a[a[-1]])

print(a[a[a[a[2]+1]]] )

 

(f)

for x in [1, 2]:

    for y in [3, x]:

        print (x, y)

 

 

Answer =

 

Output:-

(a)

[18, 2, 3]

1

>>> 

 

(b)

[18, 2, 3]

22

>>> 

 

(c)

4

-4

[3, 4] 2

>>> 

 

(d)

[5, 0]

>>> 

 

(e)

55

0

Traceback (most recent call last):

  File "C:\Desktop\Q7.py", line 4, in <module>

    print(a[a[0]] )

IndexError: list index out of range

>>> 

 

(f)

1 3

1 1

2 3

2 2

>>> 

 

 

 

 

 

 

Q8. Write a program to find the median, from a given list.

 

Answer =

 

lst = eval(input ("Enter the List :- "))

lst.sort()

if len(lst) % 2 == 0 :

    print ("Median :- ", lst[ int (len(lst) / 2 )])

else :

    print ("Median :- ", lst[ int ((len(lst) + 1) / 2 )])

 

 

 

 

 

 

Q9. Write a program to find the mode, from a given list.

 

Answer =

 

lst = eval(input ("Enter the List :- "))

feq = []

for i in lst :

    feq += [lst.count(i)]

feq.sort()

for i in lst :

    if feq[-1] == lst.count(i):

        print("Mode = ",i)

        break

 

 

 

 

 

 

 

Q10. Write a program to find the range, from a given list, e.g., if the given list is:

 

23,9,14,2,28, 19, 3,15,9,25,2, 4, 9

Then your code should print 26.

 

Hint. Range is the difference between the largest and lowest number. In this case 2 is largest is 28 and lowest is 2. So 28 - 2 is 26.

 

Answer =

 

lst = eval(input ("Enter the List :- "))

lst.sort()

print ("Range is :- ", lst[ len(lst) - 1] - lst[ 0 ])

 

 

 

 

 

Q11. Cumulative sum of a list [a, b, c...] is defined as [a, a + b, a + b + c, ...). Write a program to input a list of number and then create another list from this list that contains cumulative sum of numbers in list1.

 

 

Answer =

 

lst = eval(input ("Enter the List :- "))

lst1 = [  ]

sum = 0

for i in lst :

    sum += i

    lst1 += [ sum ]

print(lst1)