Resources for preparing for SDE2/SDE3 roles

Software Design principals and patterns. (Design Patterns) 

1. https://bytebytego.com/

2. https://refactoring.guru/

Python library for all standard data structures.

 pygorithm-module-in-python/

# Help on package pygorithm.data_structures
help(data_structures)
Output:
NAME
    pygorithm.data_structures - Collection of data structure examples

PACKAGE CONTENTS
    graph
    heap
    linked_list
    quadtree
    queue
    stack
    tree
    trie

#Example 1:

# import the required data structure
from pygorithm.data_structures import stack


# create a stack with default stack size 10
myStack = stack.Stack()

# push elements into the stack
myStack.push(2)
myStack.push(5)
myStack.push(9)
myStack.push(10)

# print the contents of stack
print(myStack)

# pop elements from stack
myStack.pop()
print(myStack)

# peek element in stack
print(myStack.peek())

# size of stack
print(myStack.size())

Output:
2 5 9 10
2 5 9
9
3

#Example 2:

# to get code for BinarySearchTree

BStree = tree.BinarySearchTree.get_code()

print(BStree)

Output:
class BinarySearchTree(object):
   
    def __init__(self):
        self.root = None

    def insert(self, data):
        """
        inserts a node in the tree
        """
        if self.root:
            return self.root.insert(data)
        else:
            self.root = BSTNode(data)
            return True

    def delete(self, data):
        """
        deletes the node with the specified data from the tree
        """
        if self.root is not None:
            return self.root.delete(data)

    def find(self, data):
        if self.root:
            return self.root.find(data)
        else:
            return False

    def preorder(self):
        """
        finding the preorder of the tree
        """
        if self.root is not None:
            return self.root.preorder(self.root)

    def inorder(self):
        """
        finding the inorder of the tree
        """
        if self.root is not None:
            return self.root.inorder(self.root)

    def postorder(self):
        """
        finding the postorder of the tree
        """
        if self.root is not None:
            return self.root.postorder(self.root)
    
    @staticmethod
    def get_code():
        """
        returns the code of the current class
        """
        return inspect.getsource(BinarySearchTree)

Example 3:

To get complexities for the following scripts:
# create a stack with default stack size 10
Bsort = sorting.bubble_sort.time_complexities()
Output:
Best Case: O(n), Average Case: O(n ^ 2), Worst Case: O(n ^ 2).

For Improved Bubble Sort:
Best Case: O(n); Average Case: O(n * (n - 1) / 4); Worst Case: O(n ^ 2)

Source code of this package: https://github.com/OmkarPathak/pygorithm

Integer caching in python

 Python (specifically the default CPython implementation) uses integer caching to optimize performance and memory usage by pre-allocating a range of commonly used small integer objects. 

How Integer Caching Works

• Cached Range: CPython pre-loads all integer objects in the range of -5 to 256 during interpreter startup.
• Singleton Instances: When you assign a variable an integer value within this range, Python simply returns a reference to the existing, pre-allocated object rather than creating a new one. This makes each integer in this range a singleton.
• Memory and Performance: This optimization saves significant memory and computation time because small integers are used very frequently (e.g., as loop counters or list indices).
• Immutability: Integer caching is safe because integers are immutable data types. Sharing the same object across multiple variables does not cause issues, as any operation that appears to modify an integer actually creates a new integer object. 

Key Behaviors and Examples

The effect of integer caching is most apparent when using the operator, which checks for object identity (same memory location) rather than value equality ( operator).

• Within the Cached Range:
• >>> a = 100
• >>> b = 100
• >>> a is b
• True
• >>> id(a) == id(b)
• True
• and point to the same memory location because 100 is within the range.
• Outside the Cached Range (in the Python REPL):
• >>> x = 257
• >>> y = 257
• >>> x is y
• False
• >>> id(x) == id(y)
• False
• and are different objects with different memory locations because 257 is outside the cached range. 

Compiler Optimization (Scripts vs. REPL)

Interestingly, the behavior for integers outside the range can differ between a Python interactive shell (REPL) and running code from a Python file (script).

• When running a whole script, the Python compiler can optimize and reuse identical integer literals even outside the standard range, making return for .
• In the REPL, code is compiled line-by-line, limiting this optimization and making the distinct object creation more apparent. 

Best Practices

Do not rely on the operator for integer value comparison, except when checking for (which is always a singleton). The behavior of for integers can vary across different Python implementations (e.g., CPython, PyPy) and even different versions of the same implementation. 

Always use the operator to check if two variables have the same value. 

What apparatus is used to measure the electrostatic force between two objects

 A torsion balance is the apparatus used to measure the electrostatic force between two objects. This device, famously used by Charles-Augustin de Coulomb, uses a suspended rod with a charged ball and measures the force by the twist of a fiber, which is proportional to the torque created by the electrostatic repulsion or attraction.

• Torsion Balance: This is a sensitive instrument consisting of a rod suspended from its center by a thin fiber.
• How it works: A charged object is placed near a second charged ball on the rod. The resulting electrostatic force causes the rod to twist the fiber through a specific angle. By measuring this angle and knowing the properties of the fiber, the force can be calculated. [1, 4, 5]

AI responses may include mistakes.

[1] https://en.wikipedia.org/wiki/Coulomb%27s_law

[2] https://flexbooks.ck12.org/cbook/ck-12-physics-flexbook-2.0/section/15.3/related/rwa/electrolytically-charged-sphere/

[3] https://klingereducational.com/blogs/the-klinger-blog/coulombs-law-apparatus

[4] https://askfilo.com/user-question-answers-smart-solutions/how-would-you-design-an-experiment-to-precisely-measure-the-3337353932343639

[5] https://pm.szczecin.pl/uploads/imfich/zaklad-fizyki/09-Electric-Fields.pdf

What apparatus is used to measure the gravitational force between two objects?

 The primary apparatus for measuring the gravitational force between two objects is a torsion balance, famously used in the Cavendish experiment. For measuring the gravitational force of a planet, a gravimeter is used, which can be based on a spring or a free-fall method. [1, 2, 3, 4, 5]

Torsion Balance

• Principle: This device measures the extremely small twist in a wire caused by the gravitational pull between two large, known masses and two smaller masses suspended at the ends of a rod.
• Function: By measuring the angle of the twist (often using a mirror and laser pointer), the force can be calculated. This was the first method to accurately measure the gravitational constant, . [4, 5, 6, 7, 8]

Gravimeter

• Principle: A gravimeter is used to measure the Earth's gravitational field, which is a measure of gravitational acceleration (). It works on the principle that gravitational force is a type of acceleration.
• Function: It measures the gravitational force exerted by the Earth on an object.
• Spring-based gravimeters: Use a spring to counteract the force of gravity. The change in the spring's length is calibrated to the force required to balance the pull.
• Absolute gravimeters: Directly measure the acceleration of a free-falling mass in a vacuum. [1, 2, 3, 9, 10]

AI responses may include mistakes.

[1] https://brainly.in/question/60381166

[2] https://en.wikipedia.org/wiki/Gravimetry

[3] https://www.quora.com/What-is-the-device-with-which-you-can-directly-measure-the-gravitational-field-strength

[4] https://www.youtube.com/watch?v=MbucRPiL92Q

[5] https://askfilo.com/user-question-answers-science/point-to-ponder-7-how-the-value-of-was-measured-the-35303836303731

[6] https://www.youtube.com/watch?v=70-_GBymrck

[7] https://pubs.aip.org/aapt/ajp/article/84/3/234/1057019/A-simple-Cavendish-experimental-apparatus

[8] https://www.space.com/what-is-the-gravitational-constant

[9] https://www.si.edu/object/worden-gravimeter%3Anmah_865076

[10] https://www.quora.com/What-is-the-method-used-to-measure-gravitational-force

Basic Flask web app

 from flask import Flask

app = Flask(__name__)

#In Flask, URL rules can be added using either the @app.route() decorator or the app.add_url_rule() method.

@app.route('/')

def hello_world():

   return '<center><h1><I>Hello World</I></h1></center>'

def bye_world():

   return '<center><h1><I>Bye World</I></h1></center>'

app.add_url_rule('/bye', 'bye', bye_world)

if __name__ == "__main__":

   app.run(debug = True)

Query for finding high dividend paying stocks

 Post the following query in Screen.in, to get list of high dividend yield stocks:

Dividend yield > 6

AND

Dividend last year > 1000

AND

Dividend preceding year > 1000

AND

Profit after tax > 0 

_________________________________________________________________________

you can further add few more filters to know which ones are low priced now

AND

Price to Earning < Industry PE 

AND

%Down from 52w high > 20

Python Certification

 Python course from codebasics https://codebasics.io/courses/python-beginner-to-advanced?utm_source=infocard&utm_medium=yt&utm_campaign=infocard&utm_id=youtube

Also see this YT tutorial on Python https://www.youtube.com/watch?v=eykoKxsYtow&list=PLeo1K3hjS3uv5U-Lmlnucd7gqF-3ehIh0

Python script to show Laptop Battery Percentage

Source: https://www.geeksforgeeks.org/python-script-to-show-laptop-battery-percentage/

# python script showing battery details 

import psutil 

# function returning time in hh:mm:ss 

def convertTime(seconds): 

minutes, seconds = divmod(seconds, 60) 

hours, minutes = divmod(minutes, 60) 

return "%d:%02d:%02d" % (hours, minutes, seconds) 

# returns a tuple 

battery = psutil.sensors_battery() 

print("Battery percentage : ", battery.percent) 

print("Power plugged in : ", battery.power_plugged) 

# converting seconds to hh:mm:ss 

print("Battery left : ", convertTime(battery.secsleft)) 

Battery Notifier : A Python program

Source:

  (i) www.geeksforgeeks.org/create-battery-notifier-for-laptop-using-python

  (ii) stackoverflow.com - question - doing-something-before-program-exit.

NOTE: First enable 'Notifications' in your Windows PC. (Click on the Clock icon, at the right corner in the status bar and turn off the 'Do not disturb' button.  Web link: plyer-notifications-are-not-visible

#Save this  Python program as 'BatteryNotifier.py' in your 'Users' folder, and run this program in DOS #prompt, and keep the DOS window open as long as you are working on your PC.

# Install and Import the 'psutil' module, for accessing info on running processes and system utilization.

# Install and Import the 'plyer' module, for accessing features of the Hardware, like displaying Notifications on the Desktop.

 ------------------------------------------------------------------------------------------------------------

import psutil

from plyer import notification

import time

import sys

import atexit

import signal

#To handle killing the process with kill or Ctrl+C.

def kill_handler(*args):

    print("BatteryNotifier is turned OFF")

    sys.exit(0)

signal.signal(signal.SIGINT, kill_handler)

signal.signal(signal.SIGTERM, kill_handler)

 

print("Battery Notifier is ON!!")

 

#from psutil we use the sensors_battery.

while(True):

    battery = psutil.sensors_battery()

    percent = battery.percent

    if percent < 70:

        notification.notify(title="Recharge battery!! ", message=str(percent)+"% Battery remaining", timeout=30)

        

        time.sleep(35)

        

        if battery.power_plugged:

            print("Power is plugged IN")

        else:

            notification.notify(message = "Power is plugged OUT", timeout=30)

        

    if percent > 97:

        notification.notify(title="Battery Full!! ", message=str(percent)+"% Battery remaining", timeout=30)

        

    

    #after every 5 mins this loop will iterate & show the respective notifications as long as anyone of the battery conditions is met.

    time.sleep(60*5)

     

    continue

------------------------------------------------------------------------------------------------------------------

Output: 

Console output at beginning of the program:

Console output when you end the program by 'Ctr + C' on command prompt:

Trending Sectors

 

1. Auto & Aviation - Tata Motors, M&M, Hero, TVS, Bajaj Auto, Inter globe aviation.
2. Banking, Finance, Broking & Insurance - Axis bk, ICICI bk, HDFC bk, SBI, AU small bk, M&M Finance, BSE, MCX, CDSL, Dixon.
3. Computer (IT & Software) - Infy, TCS, Wipro, Persistent.
4. Metals - Vedanta, Hindalco, Tata Steel.
5. Pharma - Sun, Lupin, Aurobindo, Glenmark, Divi's labs
6. FMCG - TCP, GCP, Britannia, Colgate, HUL, ITC.
7. PSU - NTPC, CIL, ONGC, HAl, BEL, BHEL, REC, PFC.
8. CG - ABB, Siemens, Cummins, Polycab, Havells, Voltas.
9. MISC - Indian Hotels, Trent, Bharti Airtel, LIC, RIL.

Derivatives stock list at NSE

Complete FNO stock list at NSE.

1. ABB India Ltd
2. ACC Ltd
3. APL Apollo Tubes Ltd
4. AU Small Finance Bank Ltd
5. Aarti Industries Ltd
6. Abbott India Ltd
7. Adani Energy Solutions Ltd
8. Adani Enterprises Ltd
9. Adani Green Energy Ltd
10. Adani Ports & Special Economic Zone Ltd
11. Adani Total Gas Ltd
12. Aditya Birla Capital Ltd
13. Aditya Birla Fashion & Retail Ltd
14. Alkem Laboratories Ltd
15. Ambuja Cements Ltd
16. Angel One Ltd
17. Apollo Hospitals Enterprise Ltd
18. Apollo Tyres Ltd
19. Ashok Leyland Ltd
20. Asian Paints Ltd
21. Astral Ltd
22. Atul Ltd
23. Aurobindo Pharma Ltd
24. Avenue Supermarts Ltd
25. Axis Bank Ltd
26. BSE Ltd
27. Bajaj Auto Ltd
28. Bajaj Finance Ltd
29. Bajaj Finserv Ltd
30. Balkrishna Industries Ltd
31. Bandhan Bank Ltd
32. Bank of Baroda
33. Bank of India
34. Bata India Ltd
35. Berger Paints India Ltd
36. Bharat Electronics Ltd
37. Bharat Forge Ltd
38. Bharat Heavy Electricals Ltd
39. Bharat Petroleum Corporation Ltd
40. Bharti Airtel Ltd
41. Biocon Ltd
42. Birlasoft Ltd
43. Bosch Ltd
44. Britannia Industries Ltd
45. CESC Ltd
46. CG Power & Industrial Solutions Ltd
47. Can Fin Homes Ltd
48. Canara Bank
49. Central Depository Services (India) Ltd
50. Chambal Fertilisers & Chemicals Ltd
51. Cholamandalam Investment & Finance Company Ltd
52. Cipla Ltd
53. City Union Bank Ltd
54. Coal India Ltd
55. Coforge Ltd
56. Colgate-Palmolive (India) Ltd
57. Computer Age Management Services Ltd
58. Container Corporation Of India Ltd
59. Coromandel International Ltd
60. Crompton Greaves Consumer Electricals Ltd
61. Cummins India Ltd
62. Cyient Ltd
63. DLF Ltd
64. Dabur India Ltd
65. Dalmia Bharat Ltd
66. Deepak Nitrite Ltd
67. Delhivery Ltd
68. Divis Laboratories Ltd
69. Dixon Technologies (India) Ltd
70. Dr Lal Pathlabs Ltd
71. Dr Reddys Laboratories Ltd
72. Eicher Motors Ltd
73. Escorts Kubota Ltd
74. Exide Industries Ltd
75. FSN E-Commerce Ventures Ltd
76. Federal Bank Ltd
77. GAIL (India) Ltd
78. GMR Airports Ltd
79. Glenmark Pharmaceuticals Ltd
80. Godrej Consumer Products Ltd
81. Godrej Properties Ltd
82. Granules India Ltd
83. Grasim Industries Ltd
84. Gujarat Gas Ltd
85. Gujarat Narmada Valley Fertilizers & Chemicals Ltd
86. HCL Technologies Ltd
87. HDFC Asset Management Company Ltd
88. HDFC Bank Ltd
89. HDFC Life Insurance Company Ltd
90. HFCL Ltd
91. Havells India Ltd
92. Hero MotoCorp Ltd
93. Hindalco Industries Ltd
94. Hindustan Aeronautics Ltd
95. Hindustan Copper Ltd
96. Hindustan Petroleum Corporation Ltd
97. Hindustan Unilever Ltd
98. Housing & Urban Development Corporation Ltd
99. ICICI Bank Ltd
100. ICICI Lombard General Insurance Company Ltd
101. ICICI Prudential Life Insurance Company Ltd
102. IDFC First Bank Ltd
103. IRB Infrastructure Developers Ltd
104. ITC Ltd
105. Indiamart Intermesh Ltd
106. Indian Bank
107. Indian Energy Exchange Ltd
108. Indian Hotels Co Ltd
109. Indian Oil Corporation Ltd
110. Indian Railway Catering & Tourism Corporation Ltd
111. Indian Railway Finance Corporation Ltd
112. Indraprastha Gas Ltd
113. Indus Towers Ltd
114. IndusInd Bank Ltd
115. Info Edge (India) Ltd
116. Infosys Ltd
117. Interglobe Aviation Ltd
118. Ipca Laboratories Ltd
119. J K Cements Ltd
120. JSW Energy Ltd
121. JSW Steel Ltd
122. Jindal Stainless Ltd
123. Jindal Steel & Power Ltd
124. Jio Financial Services Ltd
125. Jubilant Foodworks Ltd
126. KEI Industries Ltd
127. KPIT Technologies Ltd
128. Kalyan Jewellers India Ltd
129. Kotak Mahindra Bank Ltd
130. L&T Finance Ltd
131. L&T Technology Services Ltd
132. LIC Housing Finance Ltd
133. LTIMindtree Ltd
134. Larsen & Toubro Ltd
135. Laurus Labs Ltd
136. Life Insurance Corporation of India
137. Lupin Ltd
138. MRF Ltd
139. Macrotech Developers Ltd
140. Mahanagar Gas Ltd
141. Mahindra & Mahindra Financial Services Ltd
142. Mahindra & Mahindra Ltd
143. Manappuram Finance Ltd
144. Marico Ltd
145. Maruti Suzuki India Ltd
146. Max Financial Services Ltd
147. Max Healthcare Institute Ltd
148. Metropolis Healthcare Ltd
149. Mphasis Ltd
150. Multi Commodity Exchange of India Ltd
151. Muthoot Finance Ltd
152. NBCC (India) Ltd
153. NCC Ltd
154. NHPC Ltd
155. NMDC Ltd
156. NTPC Ltd
157. National Aluminium Company Ltd
158. Navin Fluorine International Ltd
159. Nestle India Ltd
160. Oberoi Realty Ltd
161. Oil & Natural Gas Corpn Ltd
162. Oil India Ltd
163. One 97 Communications Ltd
164. Oracle Financial Services Software Ltd
165. P I Industries Ltd
166. PB Fintech Ltd
167. PVR Inox Ltd
168. Page Industries Ltd
169. Persistent Systems Ltd
170. Petronet LNG Ltd
171. Phoenix Mills Ltd
172. Pidilite Industries Ltd
173. Piramal Enterprises Ltd
174. Polycab India Ltd
175. Poonawalla Fincorp Ltd
176. Power Finance Corporation Ltd
177. Power Grid Corporation of India Ltd
178. Prestige Estates Projects Ltd
179. Punjab National Bank
180. RBL Bank Ltd
181. REC Ltd
182. Reliance Industries Ltd
183. SBI Cards & Payment Services Ltd
184. SBI Life Insurance Company Ltd
185. SJVN Ltd
186. SRF Ltd
187. Samvardhana Motherson International Ltd
188. Shree Cement Ltd
189. Shriram Finance Ltd
190. Siemens Ltd
191. Solar Industries India Ltd
192. Sona BLW Precision Forgings Ltd
193. State Bank of India
194. Steel Authority of India Ltd
195. Sun Pharmaceuticals Industries Ltd
196. Sun TV Network Ltd
197. Supreme Industries Ltd
198. Syngene International Ltd
199. TVS Motor Company Ltd
200. Tata Chemicals Ltd
201. Tata Communications Ltd
202. Tata Consultancy Services Ltd
203. Tata Consumer Products Ltd
204. Tata Elxsi Ltd
205. Tata Motors Ltd
206. Tata Power Company Ltd
207. Tata Steel Ltd
208. Tech Mahindra Ltd
209. The Ramco Cements Ltd
210. Titan Company Ltd
211. Torrent Pharmaceuticals Ltd
212. Torrent Power Ltd
213. Trent Ltd
214. Tube Investments of India Ltd
215. UPL Ltd
216. UltraTech Cement Ltd
217. Union Bank of India
218. United Breweries Ltd
219. United Spirits Ltd
220. Varun Beverages Ltd
221. Vedanta Ltd
222. Vodafone Idea Ltd
223. Voltas Ltd
224. Wipro Ltd
225. Yes Bank Ltd
226. Zomato Ltd
227. Zydus Lifesciences Ltd
     
 

My stock scanners

1. Bullish stocks
2. Bearish stocks
   

Machine Learning certification course

A certification course in ML by Code Basics 

Complete list of all Python libraries

 Get all Python library list here pypi

What is a data structures

 

Data structure is a tool in the hands of a programmer for storing a large number of data items in the main memory (RAM) of a computer which can be reference by a single name, to enable their efficient storing, access and modification during program execution. 

It can also be understood as a specialized format (layout) for storing, processing and retrieving data.