List Manipulation || Sumita Arora || Class 11 || Practical || Computer Science || Solution

List Manipulation || Sumita Arora || Class 11 || Practical || Computer Science || Solution

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] = []

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?

(b) How many elements does it contain? What are their types?

(c) How many integers?

(d) What does len(a[2]) return?

(e) What does a[len(a)] evaluate to?

(f) What does a [-1 * len(a)] evaluate to?

Q3. Taking the list a = [1, 2, [3, 4], 5], after we make a[1:2] = [[2, 3], 4]. Verify your answers in Python Shell.

(a) What is the length of a ?

(b) How many elements does it contain?

(c) How many integers ?

(d) What does len(a[1] + a[3]) return?

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

P.I.P: - 7.2

Q1. Create a list L containing first 10 even numbers. Write statements (one statement per task) for the following:

(a) Change elements from index 4 to 9 to first 5 odd numbers in single statement.

(b) Add the replaced even numbers to the end of the list.

(c) Remove the middle element of the list. If two elements are at the middle of a list, delete the second one.

(d) Sort the list in reverse order.

Q2. Here is a partially completed program code that takes a list of strings and prints long string that is the concatenation of all the strings in the list, taken in order.

For example, if the given list L is ["These", "are", "hello"] then the program would print "Thesearehello".

There is some code missing in this program. Your task is to supply this. (Verify your answer by running the complete code in Python)

# input list here

bigstring = " " #empty string

for i in range(len(L)):

# Fill in the blank line below

    ---------------------

print (bigString)

Q3. Here is a partially completed code that takes two lists and prints "Yes, List1 is a subset of List2" if every element of the first list is also in the second list; otherwise, the code prints "No, list1 not a subset of list2". (Verify your code by running your complete code in Script mode)

For example if the first list is [3, 8.5, -22] and the second list is ["hello", -22, "hi", 8.5, "goblin", 3] then code would print "Yes...". On the other hand, if the first list is [3, 8.5, -22] and the second list if ["hello", -22, "hi", "goblin", 3] then the code would print "No...". There is some code missing in this code. Your task is to supply this.

#Input lists here

for e in L1:

    # Fill in the statement below

    if e not in L2:

    ----------------------

#print statements here

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.

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.

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.

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)

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

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

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.

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.