Python with Data Science

Assignment 3

Due date: 2019-09-23, 23:59 IST.

Your last recorded submission was on 2019-09-17, 17:21 IST

Get description about the data files by clicking on the following links :

mtcars_DataDescription

Diamond_DataDescription

Churn_DataDescription

1 point

The command used for reading a text file in python is: -

 read_ csv 

 read_table 

 read_ excel

 both a and b

1 point

The command used for line plot from the package Matplotlib?

 plot( )

 line( )

 join( )

 plt( ) 

1 point

From the given dataset ‘mtcars.csv’, plot a histogram to check the frequency distribution of the variable ‘mpg’ (Miles per gallon). The interval having the
   highest frequency is: -

 10 to 15

 15 to 20

 25 to 30

 30 to 35

1 point

Which of the following can be inferred from scatter plot of ‘mpg’ (Miles per gallon) vs ‘wt’ (Weight of car) from the dataset mtcars.csv?

 As weight of the car increases, the mpg decreases

 As weight of the car increases, the mpg increases

 There is no relation between weight of the car and mpg

 When weight increases, mpg increases exponentially

1 point

The command from seaborn library that is used to plot the relationship between two numerical variables 

 plotreg( )

 plot( )

 pair( )

 regplot( )

1 point

The function from seaborn library that combines regplot() and FacetGrid is

 regplot( )

 boxplot( )

 lmplot( )

 pairplot( )

1 point

The visual representation of the statistical five number summary of variable (s) is given by

 Pair-plot

 Box-and-Whisker plot

 Scatter plot

 Histogram

1 point

Plot a boxplot for “price” vs “cut” from the dataset “diamond.csv”. Which of the categories under “cut” have the highest median price?

 Good

 Ver Good

 Premium

 Fair

1 point

Create a frequency table (one-way table) for the variable “cut” from the dataset “diamond.csv”. What is the frequency for the cut type “Ideal”?

 13791

 12082

 21552

 21551

1 point

The probability of two different events occurring at the same time is known as

 Marginal probability

 Conditional probability

 Joint probability

 Marginal and Joint probability

1 point

The command to detect NaN (null) values in pandas dataframes is

 isna( ) 

 isnull( )

 isnan( )

 Both a and b

1 point

The command to identify the data type of a column in the dataframe is

 DataFrame.column_name.dtypes

 DataFrame.column_name.ftypes

 DataFrame.column.dtype

 All the above

Read the given data “churn.csv” and save it as a dataframe called churn, and answer the questions from 13 to 18

1 point

The no. of duplicate records in the churn dataframe based on the cutomerID column are

 7

 8

 22

 No duplicates

1 point

In the churn dataframe, what are the total no. of missing values for the variable TotalCharges?

 10

 23

 15

 5

1 point

From the churn dataframe, what is the average monthly charge paid by a customer for the services he/she has signed up for?

 72.56

 62.47

 68.86

 78.58

1 point

In the churn dataframe, under the variable Dependents how many records have “1@#" ?

 9

 6

 2

 8

1 point

The data type of the variable tenure from the churn dataframe is

 int64

 float64

 long

 object

1 point

The command to replace ‘Four’ by 4 and ‘One’ by 1 under the variable “tenure” of the churn dataframe: -

 pandas.Dataframe.where()

 pandas.Dataframe.replace()

 numpy.where()

 all the above

1 point

The Pearson correlation coefficient value ranges from

 0 to 1

 -1 to 1

 -1 to 0

 None of the above

1 point

In control structures, to mark the beginning of sequence of operations, ----- is used

 Curly braces – { }

 Semi colon - ;

 Indentation – (blank space)

 Square bracket - [ ]

You may submit any number of times before the due date. The final submission will be considered for grading.

Python NPTEL

Python with Data Science

netaji gandi Monday, September 23, 2019

Programming, Data Structures And Algorithms Using Python

Week 7 Quiz

Due date: 2019-09-18, 23:59 IST.

Your last recorded submission was on 2019-09-11, 15:58 IST

All questions carry equal weightage. All Python code is assumed to be executed using Python3. You may submit as many times as you like within the deadline. Your final submission will be graded.

Note:

• If the question asks about a value of type string, remember to enclose your answer in single or double quotes.
• If the question asks about a value of type list, remember to enclose your answer in square brackets and use commas to separate list items.

Given the following permutation of a,b,c,d,e,f,g,h,i,j, what is the next permutation in lexicographic (dictionary) order? Write your answer without any blank spaces between letters.

    eibjdhgfca

    [e,i,b,j,f,a,c,d,g,h]

2.5 points

2.5 points

We want to add a function listmax() to the class Node that implements user defined lists such that listmax() computes the maximum value in a list where values are of type int.

An incomplete implementation of listmax() given below. You have to provide expressions to put in place of AAA, BBB and CCC.

    
     def listmax(self):
        if self.value == None:
            return(AAA)
        elif self.next == None:
            return(BBB)
        else:
            return(CCC)

 AAA: 0, BBB: self.value, CCC: max(self.value, self.next.listmax())

 AAA: 0, BBB: self.value, CCC: max(self.value, self.next.value)

 AAA: None, BBB: self.value, CCC: max(self.value, self.next.listmax())

 AAA: None, BBB: self.value, CCC: max(self.value, self.next.value)

2.5 points

Suppose we add this function foo() to the class Tree that implements search trees. For a name mytreewith a value of type Tree, what would mytree.foo() compute?

    def foo(self):
        if self.isempty():
            return(0)
        elif self.isleaf():
            return(1)
        else:
            return(self.left.foo() + self.right.foo()))

 The number of nodes in mytree

 The largest value in mytree.

 The length of the longest path from root to leaf in mytree.

 The number of leaves in mytree.

Inorder traversal of a binary tree has been defined in the lectures. A postorder traversal lists the vertices of a binary tree (not necessarily a search tree) as follows:

• Print the left subtree in postorder.
• Print the right subtree in postorder.
• Print the root. 

Suppose we have a binary tree with 10 nodes labelled a, b, c, d, e, f, g, h, i, j, with postorder traversal ehicbjfadg and inorder traversal ehbicgjafd. What is the left child of the root node?

  [b]

Python NPTEL

Programming, Data Structures And Algorithms Using Python

netaji gandi Tuesday, September 17, 2019

NPTEL » Programming, Data Structures And Algorithms Using Python

Week 6 Quiz

Due date: 2019-09-11, 23:59 IST.

Your last recorded submission was on 2019-09-11, 15:49 IST

All questions carry equal weightage. All Python code is assumed to be executed using Python3. You may submit as many times as you like within the deadline. Your final submission will be graded.

Note:

• If the question asks about a value of type string, remember to enclose your answer in single or double quotes.
• If the question asks about a value of type list, remember to enclose your answer in square brackets and use commas to separate list items.

2.5 points

Suppose u and v both denote sets in Python. Under what condition can we guarantee that u - (u - v) == v?

 The sets u and v should be disjoint.

 The set v should be a subset of the set u.

 The set u should be a subset of the set v.

 This is true for any u and v.

2.5 points

Suppose u and v both denote sets in Python. Under what condition can we guarantee that u|v == u^v?

 The sets u and v should be disjoint.

 The set u should be a subset of the set v.

 The set v should be a subset of the set u.

 This is true for any u and v.

Suppose we insert 97 into the max heap [98,67,89,38,42,54,89,17,25]. What is the resulting heap?

[98,97,89,38,67,54,89,17,25,42]

2.5 points

Suppose we we apply delete_max() twice to the heap [100,97,93,38,67,54,93,17,25,42].  What is the resulting heap?

[93,67,93,38,42,54,25,17]

Python NPTEL

NPTEL » Programming, Data Structures And Algorithms Using Python

netaji gandi Wednesday, September 11, 2019

NPTEL » Python for Data Science

Assignment 2

Due date: 2019-09-11, 23:59 IST.

Your last recorded submission was on 2019-09-10, 10:56 IST

1 point

Package that deals with dataframe is

 numpy

 dataframe

 pandas

 math

1 point

The data type of the following python object 'a' is: a={23, 24, 25, 26, 27}

 list

 dictionary

 set

 arrays

1 point

Variable ‘a’ is defined as
       a = ‘gOOd moRning’
       Command to convert ‘a’ from ‘gOOd moRning’ to ‘Good Morning’ is:-

 a.upper( )

 a.lower( )

 a.string( )

 a.title( )

1 point

Which of the following python data structure is immutable?

 list

 dictionary

 tuple

 array

1 point

Identify the braces used to create a dictionary in Python.

 ( )

 { }

 [ ]

 All of the above

1 point

The command used to add elements to a list

 append( )

 extend( )

 insert( )

 all of the above( )

Using the list ‘Stationery’ answer questions 7-8

Product = ['Pencil', 'Pen', 'Eraser', 'Pencil Box', 'Scale']

Price= [5, 10, 2, 20, 12]  

Brand = ['Camlin', 'Rotomac', 'Nataraj', 'Camel', 'Apsara']

Stationery = [Product, Price, Brand]

1 point

The command to add “Notebook” as the first element inside the first level of the list      “Stationery” is:-

 Stationery[0].append('Notebook')

 Stationery[0].insert(0,'Notebook')

 Stationery[0][1] = "Notebook"

 Stationery[0].extend('Notebook')

1 point

Command to replace the element of Brand, “Camel” with “Camlin” inside the list is:-

 Stationery[2][3].append('Camlin')

 Stationery[2].insert(3,'Camlin')

 Stationery[2][3] = "Camlin"

 none of the above

1 point

The list "Months" is defined as:-

       Months = ['Jan', 'Mar', 'June', 'Aug', 'June', 'Feb', 'Nov', 'Dec', 'June', 'Apr', 'May',     'June']

       Which of the following commands returns the number of occurrences of ‘June’?

 Months.count('June')

 Months.len('June')

 Months[‘June’].count()

 Months[‘June’].len()

1 point

 Choose the correct command to sort 'Ages' in ascending order

    Ages = [ ’20’, ‘26’, ‘56’, ‘54’, ‘32’, ‘28’, ‘23’, ‘99’, ‘87’, ‘10’, ‘65’, ‘88’, ‘66’,
                  ‘48’, ‘42’, ‘27’, ‘33’, ‘38’,  ‘83’, ‘94’, ‘66’, ‘44’]

 sorted(Ages, reverse=False)

 Ages.sort()

 sorted(Ages, reverse=True)

 both A and B

Answer questions 11 and 12 using the information given below: 
   

 D = [‘MONDAY’, ‘TUESDAY’,  ‘WEDNESDAY’, ‘THURSDAY’, ‘FRIDAY’, ‘SATURDAY’, ‘SUNDAY’]

1 point

 The command to print WEDNESDAY, THURSDAY from the list “D” is

 print(D[-5], D[-4])

 print(D[3], D[4])

 print(D[2:5]) 

 all of the above

1 point

 The command used to reverse the above list “D” is:-

 reverse(D)

 D.reverse()

 list(reversed(D))

 both B and C

1 point

 The command to clear all the elements from a Set is:-

 remove( )

 discard( )

 clear( )

 all of the above( )

Answer questions 14 and 15 using the information given below:   

Mylist =[‘a’, ‘a’, ‘b’, ‘b’, ‘b’, ‘c’, ‘c’, ‘d’, ‘e’] 

1 point

 The output of the code: Mylist.index(‘d’) is

 7

 8

 4

 6

1 point

 The output after you run the command:
         Mylist.pop(0)         print(Mylist)

 [‘a’, ‘a’, ‘b’, ‘b’, ‘b’, ‘c’, ‘c’, ‘d’, ‘e’]

 [‘a’, ‘b’, ‘b’, ‘b’, ‘c’, ‘c’, ‘d’, ‘e’]

 [‘a’, ‘a’ ‘b’, ‘b’, ‘b’, ‘c’, ‘c’, ‘d’] 

 [‘b’, ‘b’, ‘b’, ‘c’, ‘c’, ‘d’, ‘e’]

1 point

 The command to find the number of elements in the following list “N”
          N = [24, 27, 29, 26, 25, 23, 20]

 len(N)

 N.count()

 N.len()

 count(N)

Create a dictionary ‘Country’ that maps the following countries to their capitals respectively. 

1 point

 The command to replace “Sydney” with “Canberra” is:-

 Country['Australia']="Canberra"

 Country.update({"Australia":"Canberra"})

 Both A and B

 None of the above

Create the following sets X1 and X2 using the data provided below and answer the questions 18 and 19

1 point

 The output of X1.intersection(X2) will be

 {0,1,7,8}

 {1,3,7,8}

 {1,2,7,8}

 {1,4,7,8}

1 point

 The command X1.symmetric_difference(X2)

 returns all elements belonging to both set X1 and X2

 returns elements belonging to X1 but not X2

 returns elements not common to both sets X1 and X2

 returns elements common to X1 and X2

1 point

Which of the following is a code template for creating objects in Python?

 list

 set

 dictionary 

 class

Create the following Matrix “Y” in Python and answer questions 21 to 23 :

1 point

  The determinant of the matrix “Y” rounded off to the zeroth decimal place is

 110

 120

 0

 1

1 point

  Inverse of matrix “Y” rounded off to second decimal place is

 ([[- 0.73, 0.68, 0.11],

 [0.09,  -0.27, 0.04],

 [0.18,  0.05,  -0.13]])

([[ 0.73, -0.68, -0.11],

[-0.09,  0.27, -0.04],

[-0.18,  0.05,  0.13]])

 ([[ 0.73, 0.68, 0.11],

[0.09,  0.27, 0.04],

[0.18,  0.05,  0.13]])

([[- 0.73, -0.68, -0.11],

[-0.09,  -0.27, -0.04],

[-0.18,  -0.05, -0.13]])

1 point

  The column sum of YT is

 matrix([[11, 27, 25]])

 matrix([[19, 14, 25]])

 matrix([[19, 14, 30]])

 matrix([[11, 27, 30]])

Python NPTEL

NPTEL » Python for Data Science

netaji gandi