PFA - Mid semester exam answer sheet

Deepak Sharma (Instructor-in-Charge)

Question no. 1

Answer

A-8

B-9

C-7

D-6

E-10

F-2

G-4

H-3

I-1

J-5

Question no. 2

Code demonstration

In R str() function provides the type of data structure

a <- 5
str(a)

##  num 5

a <- '5'
str(a)

##  chr "5"

In Python str() function provides type-casting (conversion of a data type into string data type)

a = 5
type(a)

## <class 'int'>

a = str(a)
type(a)

## <class 'str'>

Question no. 4

R code for demonstration

dist <- rnorm(n = 1000, mean = 100, sd = 10)
hist(dist)

boxplot(dist)

pie(dist)

plot(dist, type = 'l')

Question no. 5

All 5 options print the element ‘l’ from ‘Hello’ string.

In Python

Indexing starts from 0 from Left side. Indexing from right side starts from -1.

Therefore indices for following string would be

#Python indexing
#   0   1   2   3   4
#   H   E   L   L   O
#  -5  -4  -3  -2  -1

Code demonstration

Name = "Hello"
print(Name[3])

## l

print(Name[-2])

## l

print(Name[-3])

## l

print(Name[-1-1-1])

## l

print(Name[1+1])

## l

Question no. 6

Dot chart

dotchart(iris$Sepal.Width[1:30], pch = 17)
abline(v = 3) # Four flowers having same sepal width (3) are not overlapping

Violin plot

dist <- rnorm(n = 1000, mean = 100, sd = 10)
library("vioplot")
vioplot(dist) # Includes Histogram + Boxplot

Question no. 10

Output of following Python code

import numpy as np

def loop(input_list):
  loop_list = [0, 0, 0, 0]
  for i in range(1, len(input_list)):
    if i < 4:
      loop_list[i-1] = input_list[i] - input_list[i-1]
  return(loop_list)

input_list1 = [10, 20, 30, 40]
input_list2 = [2, 4, 15]
output = []

try:
  output = np.divide(input_list1, input_list2)
  print("1")
except:
  print("2")
  input_list2.append(20)
  output = np.divide(input_list1, input_list2)
  if output[-2] == 2:
    print(output[3])
    print(loop(output))
  else:
    loop(input_list1)
finally:
  print("4")

## 2
## 2.0
## [0.0, -3.0, 0.0, 0]
## 4

print(output)

## [5. 5. 2. 2.]

Simulation (Debugging mode)

Line no.	i	loop_list	output	input_list1	input_list2	input_list
10				[10, 20, 30, 40 ]
11				[10, 20, 30, 40 ]	[2, 4, 15 ]
12			[ ]	[10, 20, 30, 40 ]	[2, 4, 15 ]
19			[ ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]
20			[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]
3			[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
4		[ 0, 0, 0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
5	1	[ 0, 0, 0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
7	1	[ 0.0, 0, 0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
5	2	[ 0.0, 0, 0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
7	2	[ 0.0, -3.0, 0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
5	3	[ 0.0, -3.0, 0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]
7	3	[ 0.0, -3.0, 0.0, 0 ]	[ 5.0, 5.0, 2.0, 2.0 ]	[10, 20, 30, 40 ]	[2, 4, 15, 20 ]	[ 5.0, 5.0, 2.0, 2.0 ]