Q: Question 13Why should the from <module> import <object> statement be avoided to import objects ?

The from <module> import <object> statement should be avoided to import objects because it imports objects directly into the current namespace. If a program already has a variable or function with the same name as the one imported via the module, the imported object will overwrite the existing variable or function, leading to potential name clashes because there cannot be two variables with the same name in one namespace.

Question 1

Question 2What are docstrings ? What is their significance ? Give example to support your answer.

Accepted Answer

The docstrings are triple quoted strings in a Python module/program which are displayed as documentation when help () command is displayed.Significance of docstrings is as follows:Documentation — Docstrings are used to document Python modules, classes, functions, and methods.Readability — Well-written docstrings improve code readability by providing clear explanations of the code's functionality.Interactive Help — Docstrings are displayed as documentation when help () command is displayed.For example:# tempConversion.py """Conversion functions between fahrenheit and centigrade""" # Functions def to_centigrade(x): """Returns: x converted to centigrade""" return 5 * (x - 32) / 9.0 def to_fahrenheit(x): """Returns: x converted to fahrenheit""" return 9 * x / 5.0 + 32 # Constants FREEZING_C = 0.0 #water freezing temp.(in celcius) FREEZING_F = 32.0 #water freezing temp.(in fahrenheit)import tempConversion help(tempConversion)OutputHelp on module tempConversion: NAME tempConversion-Conversion functions between fahrenheit and centigrade FILE c:\python37\pythonwork empconversion.py FUNCTIONS to_centigrade(x) Returns : x converted to centigrade to_fahrenheit(x) Returns : x converted to fahrenheit DATA FREEZING_C = 0.0 FREEZING_F = 32.0

Question 2

Question 9In which order Python looks for the function/module names used by you.

Accepted Answer

Python looks for the module names in the below order :Built-in Modules — Python first looks for the module in the built-in modules that are part of the Python standard library.Directories in sys.path — If the module is not found in the built-in modules, Python searches for it in the directories listed in the sys.path variable. The directories in sys.path typically include the current directory, directories specified by the PYTHON PATH environment variable, and other standard locations such as the site-packages directory.Current Directory — Python also looks for the module in the current directory where the Python script or interactive session is running.

Question 3

Question 12What is dot notation of referring to objects inside a module ?

Accepted Answer

After importing a module using import module statement, to access one of the functions, we have to specify the name of the module and the name of the function, separated by a dot. This format is called dot notation.For example:import math
print(math.pi)
print(math.sqrt(25))

Question 4

Question 13Why should the from import

Accepted Answer

The from import

Question 5

Question 14What do you understand by standard library of Python ?

Accepted Answer

Python standard library is distributed with Python that contains modules for various types of functionalities. Some commonly used modules of Python standard library are math module, random module, cmath module etc.

Question 6

Question 15Explain the difference between import and from import statements, with examples.

Accepted Answer

import statementfrom import statementIt imports entire module.It imports single, multiple or all objects from a module.To access one of the functions, we have to specify the name of the module and the name of the function, separated by a dot. This format is called dot notation. The syntax is : .()To access functions, there is no need to prefix module's name to imported item name. The syntax is : Imports all its items in a new namespace with the same name as of the module.Imports specified items from the module into the current namespace.This approach does not cause any problems.This approach can lead to namespace pollution and name clashes if multiple modules import items with the same name.For example:import mathprint(math.pi)print(math.sqrt(25))For example:from math import pi, sqrtprint(pi)print(sqrt(25))

Question 7

Question 3Given below is semi-complete code of a module basic.py :#
"""..............."""  
def square(x):
"""..............."""
    return mul(x, x)
...............mul(x, y):
"""..............."""
    return x * y
def div(x, y):
    """..............."""
    return float(x)/y
...............fdiv(x, y)...............
"""..............."""
...............x//y
def floordiv(x, y)...............
...............fdiv(x, y)Complete the code. Save it as a module.

Accepted Answer

# basic.py
"""This module contains basic mathematical operations."""

def square(x):
    """Returns the square of a number."""
    return mul(x, x)

def mul(x, y):
    """Returns the product of two numbers."""
    return x * y

def div(x, y):
    """Returns the result of dividing x by y."""
    return float(x) / y

def fdiv(x, y):
    """Returns the result of floor division of x by y."""
    return x // y

def floordiv(x, y):
    return fdiv(x, y)The code is saved with .py extension to save it as module.

Question 8

Question 5Import the above module basic.py and write statements for the following :(a) Compute square of 19.23.(b) Compute floor division of 1000.01 with 100.23.(c) Compute product of 3, 4 and 5. (Hint. use a function multiple times).(d) What is the difference between basic.div(100, 0) and basic.div(0, 100)?

Accepted Answer

The statements are given in the program below:import basic

# (a) Compute square of 19.23
square_result = basic.square(19.23)
print("Square of 19.23:", square_result)

# (b) Compute floor division of 1000.01 with 100.23
floor_div_result = basic.floordiv(1000.01, 100.23)
print("Floor division of 1000.01 by 100.23:", floor_div_result)

# (c) Compute product of 3, 4 and 5
product_result = basic.mul(basics.mul(3, 4), 5)
print("Product of 3, 4, and 5:", product_result)

# (d) 
result2 = basic.div(0, 100)
result1 = basic.div(100, 0)
print("Result of basic.div(100, 0):", result1)
print("Result of basic.div(0, 100):", result2)OutputSquare of 19.23: 369.79290000000003
Floor division of 1000.01 by 100.23: 9.0
Product of 3, 4, and 5: 60
Result of basic.div(0, 100): 0.0
ZeroDivisionError
Explanation(d) basic.div(100, 0) results in a ZeroDivisionError because division by zero is not defined whereas basic.div(0, 100) results in 0.0 as the quotient of '0 / 100'.

Question 9

Question 6Suppose that after we import the random module, we define the following function called diff in a Python session :def diff():
    x = random.random() - random.random() 
    return(x)What would be the result if you now evaluatey = diff()
print(y)
at the Python prompt ? Give reasons for your answer.

Accepted Answer

import random
def diff():
    x = random.random() - random.random() 
    return(x)

y = diff()
print(y)Output0.006054151450219258
-0.2927493777465524
ExplanationOutput will be a floating-point number representing the difference between two random numbers. Since every call to random() function of random module generates a new number, hence the output will be different each time we run the code.

Question 10

Question 7What are the possible outcome(s) executed from the following code? Also specify the maximum and minimum values that can be assigned to variable NUMBER.STRING = "CBSEONLINE"
NUMBER = random.randint(0, 3)
N = 9
while STRING[N] != 'L' :
    print(STRING[N] + STRING[NUMBER] + '#', end = '') 
    NUMBER = NUMBER + 1
    N = N - 1ES#NE#IO#LE#NO#ON#NS#IE#LO#EC#NB#IS#

Accepted Answer

The outcomes are as follows:ES#NE#IO#EC#NB#IS#NUMBER is assigned a random integer between 0 and 3 using random.randint(0, 3). Therefore, the minimum value for NUMBER is 0 and the maximum value is 3.ExplanationLength of STRING having value "CBSEONLINE" is 10. So the character at index 9 is "E". Since the value of N starts at 9 the first letter of output will be "E". This rules out LE#NO#ON# and NS#IE#LO# as possible outcomes as they don't start with "E". NUMBER is a random integer between 0 and 3. So, the second letter of output can be any letter from "CBSE". After that, NUMBER is incremented by 1 and N is decremented by 1.In next iteration, STRING[N] will be STRING[8] i.e., "N" and STRING[NUMBER] will be the letter coming immediately after the second letter of the output in the string "CBSEONLINE" i.e., if second letter of output is "S" then it will be "E" and if second letter is "C" then it will be "B".In the third iteration, STRING[N] will be STRING[7] i.e., "I" and STRING[NUMBER] will be the letter coming immediately after the fourth letter of the output in the string "CBSEONLINE" i.e., if fourth letter of output is "E" then it will be "O" and if fourth letter is "B" then it will be "S".After this the while loop ends as STRING[N] i.e., STRING[6] becomes "L". Thus both, ES#NE#IO# and EC#NB#IS# can be the possible outcomes of this code.

Question 11

Question 8Consider the following code :import random
print(int(20 + random.random() * 5), end = ' ')
print(int(20 + random.random() * 5), end = ' ')
print(int(20 + random.random() * 5), end = ' ')
print(int(20 + random.random() * 5))Find the suggested output options 1 to 4. Also, write the least value and highest value that can be generated.20 22 24 2522 23 24 2523 24 23 2421 21 21 21

Accepted Answer

23 24 23 2421 21 21 21The lowest value that can be generated is 20 and the highest value that can be generated is 24.Explanationimport random — This line imports the random module.print(int(20 + random.random() * 5), end=' ') — This line generates a random float number using random.random(), which returns a random float in the range (0.0, 1.0) exclusive of 1. The random number is then multiplied with 5 and added to 20. The int() function converts the result to an integer by truncating its decimal part. Thus, int(20 + random.random() * 5) will generate an integer in the range [20, 21, 22, 23, 24]. The end=' ' argument in the print() function ensures that the output is separated by a space instead of a newline.The next print statements are similar to the second line, generating and printing two more random integers within the same range.The lowest value that can be generated is 20 because random.random() can generate a value of 0, and (0 * 5) + 20 = 20. The highest value that can be generated is 24 because the maximum value random.random() can return is just less than 1, and (0.999... * 5) + 20 = 24.999..., which is truncated to 24 when converted to an integer.

Question 12

Question 10Consider the following packagemusic/                        Top-level package
 ├── __init__.py
 ├── formats/                 Subpackage for file format
 │      ├── __init__.py
 │      └── wavread.py
 │      └── wavwrite.py
 │
 ├── effects/                 Subpackage for sound effects
 │      └── __init__.py
 │      └── echo.py
 │      └── surround.py
 │      └── reverse.py
 │
 └── filters/                 Subpackage for filters
     ├── __init__.py
     └── equalizer.py
     └── vocoder.py
     └── karaoke.py
Each of the above modules contain functions play(), writefile() and readfile().(a) If the module wavwrite is imported using command import music.formats.wavwrite. How will you invoke its writefile() function ? Write command for it.(b) If the module wavwrite is imported using command from music.formats import wavwrite. How will you invoke its writefile() function ? Write command for it.

Accepted Answer

(a) If the module wavwrite is imported using the command import music.formats.wavwrite, we can invoke its writefile() function by using the module name followed by the function name:import music.formats.wavwrite
music.formats.wavwrite.writefile()
(b) If the module wavwrite is imported using the command from music.formats import wavwrite, we can directly invoke its writefile() function without prefixing the module name:from music.formats import wavwrite
writefile()

Question 13

Question 11What are the possible outcome(s) executed from the following code ? Also specify the maximum and minimum values that can be assigned to variable PICK.import random
PICK = random.randint(0, 3)
CITY = ["DELHI", "MUMBAI", "CHENNAI", "KOLKATA"];
for I in CITY :
    for J in range(1, PICK): 
        print(I, end = " ") 
    print()DELHIDELHIMUMBAIMUMBAICHENNAICHENNAIKOLKATAKOLKATADELHIDELHIMUMBAIDELHIMUMBAICHENNAIDELHIMUMBAICHENNAIKOLKATADELHIMUMBAIMUMBAIKOLKATAKOLKATAKOLKATA

Accepted Answer

DELHIMUMBAICHENNAIKOLKATADELHIDELHIMUMBAIMUMBAICHENNAICHENNAIKOLKATAKOLKATAThe minimum value for PICK is 0 and the maximum value for PICK is 3.Explanationimport random — Imports the random module.PICK = random.randint(0, 3) — Generates a random integer between 0 and 3 (inclusive) and assigns it to the variable PICK.CITY = ["DELHI", "MUMBAI", "CHENNAI", "KOLKATA"] — Defines a list of cities.for I in CITY — This loop iterates over each city in the CITY.for J in range(1, PICK) — This loop will iterate from 1 up to PICK - 1. The value of PICK can be an integer in the range [0, 1, 2, 3]. For the cases when value of PICK is 0 or 1, the loop will not execute as range(1, 0) and range(1, 1) will return empty range.For the cases when value of PICK is 2 or 3, the names of the cities in CITY will be printed once or twice, respectively. Hence, we get the possible outcomes of this code.

Question 14

Question 1Write a Python program having following functions :A function with the following signature : remove_letter(sentence, letter)This function should take a string and a letter (as a single-character string) as arguments, returning a copy of that string with every instance of the indicated letter removed. For example, remove_letter("Hello there!", "e") should return the string "Hllo thr!".Try implementing it using <str>.split() function.Write a function to do the following :Try implementing the capwords() functionality using other functions, i.e., split(), capitalize() and join(). Compare the result with the capwords() function's result.Solutiondef remove_letter(sentence, letter):
    words = sentence.split()  
    new_sentence = []  
    for word in words:
        new_word = ''
        for char in word:
            if char.lower() != letter.lower():  
                new_word += char
        new_sentence.append(new_word)  
    return ' '.join(new_sentence)

def capwords_custom(sentence):
    words = sentence.split()  
    capitalized_words = []
    for word in words:
       capitalized_word = word.capitalize()
       capitalized_words.append(capitalized_word)
    return ' '.join(capitalized_words)

sentence = input("Enter a sentence: ")
letter = input("Enter a letter: ")
print("After removing letter:", remove_letter(sentence, letter))

from string import capwords
sentences_input = input("Enter a sentence: ")
sentences = sentences_input.split('.')

for sentence in sentences:
    sentence = sentence.strip()  
    print("Custom capwords result:", capwords_custom(sentence))
    print("Capwords result from string module:", capwords(sentence))OutputEnter a sentence: Hello there!
Enter a letter: e
After removing letter: Hllo thr!
Enter a sentence: python is best programming language
Custom capwords result: Python Is Best Programming Language
Capwords result from string module: Python Is Best Programming Language

Accepted Answer

defremove_letter(sentence,letter):words=sentence.split()new_sentence=[]forwordinwords:new_word=''forcharinword:ifchar.lower()!=letter.lower():new_word+=charnew_sentence.append(new_word)return' '.join(new_sentence)defcapwords_custom(sentence):words=sentence.split()capitalized_words=[]forwordinwords:capitalized_word=word.capitalize()capitalized_words.append(capitalized_word)return' '.join(capitalized_words)sentence=input("Enter a sentence: ")letter=input("Enter a letter: ")print("After removing letter:",remove_letter(sentence,letter))fromstringimportcapwordssentences_input=input("Enter a sentence: ")sentences=sentences_input.split('.')forsentenceinsentences:sentence=sentence.strip()print("Custom capwords result:",capwords_custom(sentence))print("Capwords result from string module:",capwords(sentence))OutputEnter a sentence: Hello there!Enter a letter: eAfter removing letter: Hllo thr!Enter a sentence: python is best programming languageCustom capwords result: Python Is Best Programming LanguageCapwords result from string module: Python Is Best Programming Language

Question 15

Question 4Create a package from above two modules as this :Conversion  
    ├──Length   
    │   └──Lengthconversion.py   
    └──Mass  
        └──Massconversion. py  
Make sure that above package meets the requirements of being a Python package. Also, you should be able to import above package and/or its modules using import command.

Accepted Answer

The basic structure of above package includes packages's name i.e., Conversion and all modules and subfolders.Create the directory structure having folders with names of package and subpackages. In the above package, we created two folders by names Length and Mass. Inside these folders, we created Lengthconversion.py and MassConversion.py modules respectively.Create __init__.py files in package and subpackage folders. We created an empty file and saved it as "__init__.py" and then copy this empty __init__.py file to the package and subpackage folders.Associate it with python installation. Once we have our package directory ready, we can associate it with Python by attaching it to Python's site-packages folder of current Python distribution in our computer.After copying our package folder in site-packages folder of our current Python installation, now it has become a Python library so that now we can import its modules and use its functions.Directory structure is as follows:Conversion/
    ├── __init__.py
    ├── Length/
    │     ├── __init__.py
    │     └── Lengthconversion.py
    └── Mass/
          ├── __init__.py
          └── MassConversion.py

Using Python Libraries

Type A Short Answer Questionsconceptual Questions

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