Python Final Lectures

Q- how to Print Hello World

print("Hello World")

Variables in python -------

age = 30 #variable should be intutive so that we can learn any time

print(age)

Note: Shift+Enter is shortcut to run command

2) '#' this is for writing the comment in python

Rules for Variables---

Variable can not be start with any number like - 1age
Number can use in between and end with variable like - age1 age2
Special characters are not allowed expect _ (underscore) like - age_my
Space not allowed in variable
Python is case sensitive

Way to define Variable ---

age1,age2 = 30,25

age1 = 30

age2 = 25

age1=age2=30 #if 30 age for both variable

>> Data type

the type of data is basically data type

Integer = age1 to age3 is basically integer , Integer is basically full number
lets check = type(age1) #it will give u print int
float= basically decimal values
Interest = 30.24
type(Interest) #answer is float
Message = Sequence of character is basically and type will be string ,Note: If we are using quote "" the it will string
Message="My Name Is Divyanshu"
type(Message) #print will str #we can use any quote 'I can use this' , "also use this" but whenever we've multiline string then will use '''triple quote'''
Boolean = 2 values are available here True and False
Like = data = False #here data is basically variable and false is data type
type(data) #give u type of data, print bool
bool

>> Mathematical Operator

Addition = +
num1 = 20
num2 = 37
result = num1+num2
print(result) #/another way direct: print(num1+num2), without storing data on new var
Substraction = -
num1 = 50
num2 = 20
result = num1-num2
print(result) #/another way direct: print(num1-num2), without storing data on new var
Multiplication = *
num1 = 20
num2 = 39
result = num1 * num2
print(result) #/another way direct: print(num1*num2), without storing data on new var
Integer Division = // #this is basically integer division
num1 = 20
num2 = 3
result = num1 // num2
print(result) #/another way direct: print(num1//num2), without storing data on new var
answer = 6, bcse it will not give u float value
Float Division = / #this is basically float division
num1 = 20
num2 = 3
result = num1 / num2
print(result) #/another way direct: print(num1/num2), without storing data on new var
answer = 6.66666666667 , bcse it is float division
Power = **
num1 = 2
num2 = 5
result = num1 ** num2
print(result)
Modulus = % #it will give u remainder
num1 = 20
num2 = 3
result = num1 % num2
print(result)
answer = 2 , it is remainder

>> How to take input from user

age1 = input() #by default it will string type data

to give age1 type so we've to typecast here
age1 = int(input())

>>Build In Functions in Python ----

len(string) = basically this is for find length of the character
string = "Divyanshu Khare" #space is also count as string
len(string) #it will give u length of the string
ls = collection of item (list)
Defined by [ ] square bracket
Example: ls[1,2,3,4,5,6]
type[ls] #it will give u type of variable
max = find maximum number of list
ls[1,2,4,5,6]
max(ls)
print(max)
min = minimum number of list
ls[1,2,3,4,5,6,7]
min(ls)
sum = sum of numbers
ls[1,2,3,4,6,7,8]
sum(ls)
len(ls) = give u lenth of list
len(ls)
max(string) = it will give u maximum ASCII value's character
string = ("Divyanshu")
max(string)
min(string) = it will give u minimum ASCII value's character
string = ("Divyanshu")
min(string)
Note: ASCII is american standard value of number's in computer
sorted(ls) = it will sort list in accending order
sorted(ls,reverse = True) = it will sort list in decending orders
round() = it will round off
round(number,what place u want to round)
example: round(12356.54645,2)
12356.55 #it will give u this as a answer
abs() = it will give u any number as a absolute(positive Number)
abs(-23538)
f = format string
example:
name = "divyanshu"
age = 30
profession = "Data Science"
introduction = f"{name} is {age} year old professional working as {profession}"
print(introduction)

>> Conditional Statement -------

if else
cibil_score = int(input("Enter Cibil Score:"))
if(cibil_score>600):
print("u re eligible for loan")
else:
print("u re not eligible")
elif = when we have more than 2 conditions
color = input("Enter color - Red, Green, Yellow")
if color == "Red":
print("Stop")
elif color == "Yellow":
print("Wait")
else:
print("Go")
loops (control structure) -- repeatation of the task
exmple: string = "Data Science"
for i in string:
print(i)
example: for i in range (0,101):
print(i)
example to print square: for i in range(0,100,2) :
print(i)
example :
ls = [1,2,3,4,5,6,7,8]
for i in ls:
print(i)
while = it will run if condition is True/ Tab tk chlega jab tk condition true hai
i = 1
while i < 10:
print("Divyanshu khare")
i = i +1
Control the loop
>> Break: it will stop all iteration once requirement finished (Stop Iteration)
ls = [1,2,3,4,5,6,7,8,9,10]
for i in ls:
if i == 6:
print("Yes")
break
>>Continue : it will stop that particular iteration only and will jump on another iteration
ls = [1,2,3,4,5,6,7,8,9,10]
for i in ls:
if i == 6:
print("Yes")
continue
>>Pass : if will do nothing, it will not break anything
ls = [1,2,3,4,5,6,7,8]
for i in ls:
if i > 0:
pass #do nothing
else:
print("Negative Number")

>>> DATA STRUCTURE IN PYTHON [this is not algorithm]

>> 4 Data structures we have

List
tuples
set
dictionary

>> Important Data Type

String operations

Indexing = process of fetching character from the collection

Example:
string = "String"
string[2]

Slicing = process of fetching sequence of character / process of fetching sub-string from the given string

Example:
string = "Data Science" #lets say I want to fetch data from this string
string[start index:end index + 1] #this is index
string[0:3 + 1]
Example 2 : If i want to slicing from right to left
string = "Data Science"
string[-11: -9]
Example 3: 👉 "If I want to slice by skipping 1 character."
string = "Data Science"
string[5:12:2]
Example 4: I want to reverse print and I dont want to put first index
string = "Data Science"
string[::-1] #If I don’t enter the first index, it will start from the 0th index

In-built function for string
string = "Data"
type(string)

len(string) = length of the string
convert string into lowercase =

string = "DIVYANSHU"
string.lower()

convert string into uppercase =

string = "divyanshu"
string.upper()

convert string into capitalize

string = "divyanshu"
new_string = string.capitalize()
print(new_string)
#Ye Python ka built-in method hai jo string ke first letter ko capital (uppercase) me badal deta hai #capitalize() se jo naya result (modified string) milta hai, wo new_string me store ho jata hai.

lstring.islower() -- it will check whether string is lowercase or uppercase

lstring = "DivyanshuJi" #lstring is basically variable
lstring.islower()

string.isupper() --- it will check whether string is uppercase or lowercase

ustring = "this is small"
ustring.isupper()

string.isdigit() --- it will check whether string is digit or not ?

numstring = "435345" #this is check string is number or not
numstring.isdigit() #numstring is basically variable name of string

string.swapcase() -- it will swap the case of given string

string = "this is small case"
string.swapcase()

string.replace("word to change", "word with change")

string = "Data science"
string.replace("a", "d") #main data sience me 'a' word ko 'd' se change kr rha

string.split() == it will split string, ("jaha se split krna hai, by default space se krta hai")

string = "Divyanshu@khare"
string.split("@")

>>>>>>>>>>>LIST - basically collection of data

ls = [1,2,34,5,6,7,"mango"]
type(ls) #to check the data type
len(ls) == #check length of list
ls[3] =#it will give u value of this index from length
ls [::-1] = #reverse list
list concatination =
ls1 = ["apple", "mango"]
ls2 = ["another"]
ls3 = ls1+ls2
print(ls3)
ls.append("apple") -= #add single element on list from end of the list
ls.extend(["grapes", "gyan"]) = #add multiple element on the list from end
ls.insert(index number,"element") = #it will add on specific index
ls.index("grapes") = it will give u positive index of the element
ls.remove("element name") = #it will remove first occurrence element wise remove, we cant remove directly all element
ls.sort() = #sort list in accending orders
ls.sort(reverse=True) = #sort list in descending order, it will change existing list
sorted(ls) #it will not change existing list
ls.pop(index number) = #it will remove element from index

>>TUPLES -------------------

ek baar ban जाने ke baad uske elements badle nahi ja sakte
Tuple is Immutable
Tuple ek data structure hai — jaise list, lekin immutable hoti hai
tuple me wo inform store krte hai jaha ham chahte hai koi bhi program intensionally ya unintensonally change na kar sake
tuple () is bracket se define krte hai
example: tup = (3,4,6,7,8544,76,34,5)
type(tup)
max(tup) = #give u maximum value of tuple
mix(tup) = #give u minimum value of tuple
sum(tup) =#give u sum of tuple
sorted(tup)
list >> tuple >> list == typecasting list to tuple and tuple to list
tup1 = tuple(ls)
tup1
tup.sort()
del = #i want to remove element from list index wise
ls = [2,3,5,6,7,4]
del ls[3] #it will not return anything

4th lecture

file handling

f = open("data.txt","r") #open is a function of python it will create and open file, "r" is used to read only, if file is in same folder will use this , basically i am trying to read data.txt file here

#now I want to access content of the file >>>
>> f.read() #it will help to read or access the file

is option se file hamesa open rhega

>> another way to read

with open ("data.txt") as f: #file open hone ke bad close ho jayega

content = f.read()

print(content)

>>read text file from google drive

# URL of the Google Sheet (public link to access the sheet data)

url = 'https://docs.google.com/spreadsheets/d/1CHNr3sioM1p6OvVx4tjNc0sMWGWp76sIBYpQdJ9H40U/edit?usp=drive_link'

# 'requests' एक Python library है जो internet (HTTP/HTTPS) से data fetch करने के लिए use होती है

import requests # Importing the requests module to send HTTP requests

# 'requests.get(url)' server ko GET request bhejta hai aur response me page ka data return karta hai

response = requests.get(url) # Sending a GET request to the given URL and storing the response in 'response'

# 'response.text' me server se mila data (HTML format me) hota hai

print(response.text) # Printing the content/text returned by the server

response.status_code # To check if the link is accessible or if there's any permission issue if 200 comes then we have access for the same

>> handle excel file

from openpyxl import Workbook # openpyxl library se Workbook class import kar rahe hain (Excel file banane ke liye)

wb = Workbook() # ek nayi (blank) Excel workbook create ho gayi (abhi memory me)

ws_new = wb.active # workbook ki default active sheet ko access kar rahe hain& ws_new me active sheet ko store kr rhe

ws_new.title = 'DataStudent' # sheet ka naam 'Sheet' se badalkar 'DataStudent' kar diya

ws_new.append(["Student name", "Grades"]) # pehli row me column headings likh rahe hain

NOTE: .append() Excel sheet में एक नई row add करने के लिए use होती है।

ws_new.append(["Baba Hunny", 70]) # dusri row me pehla student ka data add kar rahe hain

ws_new.append(["Anshika", 50]) # teesri row me data

ws_new.append(["Janvi", 50]) # chauthi row me data

wb.save("student_data.xlsx") # workbook ko system me 'student_data.xlsx' naam se save kar rahe hain

print("✅ Excel file 'student_data.xlsx' created successfully with sheet 'DataStudent'")

>> how to access the save file/read save file

from openpyxl import load_workbook #Excel file read karne ke liye openpyxl ka function import kar rahe hain

wb = load_workbook("student_data.xlsx") # Pehle se existing Excel file ko open kar rahe hain

ws_new = wb["DataStudent"] # 'DataStudent' naam wali sheet ko access kar rahe hain

for row in ws_new.iter_rows(min_row =1, values_only=True): #Ab sheet ke data ko read ya modify kar sakte ho, #min_row =1, = bcse frist row se utha rhe data

print(row)

>> CSV handle (comma seperate value)

imort csv

with oepn("titanic.csv", mode ="r" ) as f:

reader = csv.reader(f)

headers = next(reader) #to read first row

print(headers)

for i, row in (reader): # i is the index

print(row)

import csv → CSV फाइल को पढ़ने के लिए Python का built-in मॉड्यूल है।

with open("titanic.csv", mode="r") as f: → titanic.csv फाइल को read mode में खोल रहे हैं।

csv.reader(f) → फाइल की हर लाइन को एक लिस्ट की तरह पढ़ेगा।

next(reader) → पहली row (header) को निकाल देगा ताकि वो दोबारा लूप में ना आए।

enumerate(reader) → हर पंक्ति के साथ उसका index (i) देगा।

print(i, row) → हर रिकॉर्ड को उसकी क्रम संख्या (index) के साथ प्रिंट करेगा।

>> Execption handling
Try- Except Block -

try:

result = 10/0
print("This line will not be executed bcoz of error")
except ZeroDivisionError:
print("you cant divide by zero")

>> can we make more than 1 except for error handling ?
Ans: yes

Example:

try:

user_input1 = input("Enter Number")

int_input1 = int(user_input1)

user_input2 = input("Enter Number")

int_input2 = int(user_input2)

print(f"ratio of given numbers {int_input1/int_input2}")

except ZeroDivisionError: #Zero Divion ki jgh kuch or v likh skte hai ??

print("u cant divide by zero ")

except ValueError:

print("Enter the valid number")

>> #Try-Execpt-else Block

try:

user_input1 = input("Enter Number")

int_input1 = int(user_input1)

user_input2 = input("Enter Number")

int_input2 = int(user_input2)

num = int_input1/int_input2

print(f"ratio of given numbers {int_input1/int_input2}")

except ZeroDivisionError: #Zero Divion ki jgh kuch or v likh skte hai ??

print("u cant divide by zero ")

except ValueError:

print("Enter the valid number")

else: #this will only execute if no execption raised

print(f"the ratio of 2 number is {num}")

>> #Try-Except-else-finally block === in any senario chahe upr kuch bhi aaye

try:

user_input1 = input("Enter Number")

int_input1 = int(user_input1)

user_input2 = input("Enter Number")

int_input2 = int(user_input2)

num = int_input1/int_input2

print(f"ratio of given numbers {int_input1/int_input2}")

except ZeroDivisionError: #Zero Divion ki jgh kuch or v likh skte hai ??

print("u cant divide by zero ")

except ValueError:

print("Enter the valid number")

else: #this will only execute if no execption raised

print(f"the ratio of 2 number is {num}")

finally: #in any senario chahe upr kuch bhi aaye, it will executive in any senario

print("i will run")

>>write a try-except block to handle filenotfound error

try:

with open("AI.txt",r") as f:

content=f.read()

print(content)

except FileNotFoundError:

print("file not available in this path")

>>RAISE == jab exception customized raise krna hai, jo system raise nhi krega main apne requirement ke according raise krna chahta hu


def withdraw (balance, amount):  
    if balance-amount < 1000:
        raise Exception("Withdrawin denied: Minimum balance of 1000 INR to be maintaned")
    else:
        remaining = balance - amount
    return balance-amount
try:
    remaining_amount=withdraw(balance=1000, amount=2000)
    print(f"After transaction remaining balance is {remaining_amount}")
except Exception as e:
    print(f"Traction failed: {e}")
    

return ka matlab


Python me return ka kaam hai: function ke andar se koi value bahar bhejna


Matlab function calculate karke result wapas main program me deta hai
def = function define krta hai / define keyword hai
withraw = function ka naam, apne according 
(Balance, amount) = is argument
Return: Function ye value bahar bhejta hai → try block me remaining_amount variable me store hoti hai
Try blockk 
    >>withdraw(balance=5000, amount=2000)



Ye function call hai.
Matlab hum withdraw function ko execute kar rahe hain aur usme:
5000 :balance 
2000 : amount
remaining_amount
function ka return value remaining_amount variable me store ho rha hai
Mtlb withdraw ke baad bacha hua paisa ab is variable me hai
>>Built-in Modules 
#math
#random
#datetime
#os
#sys

>> import math #lets say i want to get square root
math.sqrt(34)   #yaha 34 ka square nikal rhe

>>import random #module has function to generate random data
random.random() #generate random decimal number (0-1 range tak)

random.randint(1,100)

>>from datetime import datetime  #it will give u date time
datetime.now()

>>import os #files check krne ke liye
os.getcwd() #file ka path check krne ke liye


>




numpy =numerical python , numpy ke strct numeric import krke use kr skte hai

import numpy as np  = #np is a shortname /np ki jgh kuch v de skte hai, np is a alias ise hamne isliye likha taaki in future jab bhi hame numpy likhna ho to pura likhne ke bajaye np likh ke hi upyog kr paye 

numpy jis Data sturcture pe based hai >>>>>>>>>>>

>>Array ---------
import numpy as np
arr =np.array([2,3,4,5,6,]) #list input me le rha, arr is basically variable name 
type(arr)
arr.ndim #check dimension of array, other way to check dimension , last bracket jitna hai utni dimension
>> 2 / Multi Dimension Array ------
arr2 = np.array([[1,2,3], [5,46,67]])
arr2.ndim  #arr2 is array's name and ndim will help to check dimension
  here u can see 2 brackets in this image after print 



>> arr2.shape  == #it will help us to check rows and columns of arrays
arr2 = np.array([[1,2,3], [5,46,67]])
arr2.ndim
arr2.shape

>> arr2.size ==== it will give u no of elements of array in rows only
arr2 = np.array([[1,2,3,5], [5,46,67,5]])
arr2.ndim
arr2.shape
arr2.size #no of elements

>> arr2.dtype
>>zeros_array = np.zeros((row_number, column_number))
    import numpy as np 
    zeros_array = np.zeros((10,4))  #it will give u float 0 according to row and column
    print(zeros_array)

>>ones_array = np.ones((row_number, column_number))
    import numpy as np 
    ones_array = np.ones((6,4))  #it will give u float number 1 according to row and column
    print(ones_array)
>>full_array = np.full((row_number, colum_number, fill_value = value_number)
    here full_array is variable name
    np.full = function name it will update full row number like 3, column number like 4
    fill_value = Ye parameter batata hai ki array ke sabhi elements me kya bhara jaye
Example: 
full_array = np.full((6,4), fill_value = 23)
print(full_array)


>>np.random.rand(dimension_number)
example: 
r_array=np.random.rand(5)
 


np.random.rand =  Ye NumPy ke random module ka function hai.
Ye function 0 aur 1 ke beech random numbers generate krta hai.
(dimension_number) Ye batata hai ki kitne random numbers chahiye.

>> np.round(r_array,number_round_in)
example:
r_array=np.random.rand(5)
np.round(r_array,2)

>>np.arange(start,end)
example:
arr = np.arange(1,11)
print(arr)

#yah NumPy का function है जो 1 से लेकर 10 तक की संख्याएँ generate करेगा। bcse end number 11 will not count
 

>> Indexing for single dimension array
import numpy as np
arr = np.array([1,3,4,8,5,])
arr[2]  #2 is basically index of array

>> Slicing for double dimension array
import numpy as np
arr = np.array([[1,2,3], [5,46,67]])
arr[1:2] #1 = start , 2 is end #this is for single dimension

Example:   this is for multidimentional array
#slicing in multidimentional array, lets suppose I want to slice 2 3 5 6
#arr2[start_row:end_row+1,start_column:end_column+1]
arr2 = np.array([[1,2,3,4], [4,5,6,9], [7,8,9,10]])
arr2[0:2,1:3]

>> Iteration ----------- just like literation in loop
for i in arr2:
    print(i);

>> Joining  -- if I've more than 1 array than how I can merge
#lets suppose ek hospital me 2 ward hai general and ICU jiske data ko jodna hai
general = np.array([[98,43,5345], [42,45,32]])
icu = np.array([[98,92,73], [89,42,52]])
np.concatenate((general,icu),axis = 1) #side by side (row wise merge)
#axis=1 → जोड़ना horizontally (side-by-side / row-wise)  


2nd Example: merge column wise
general = np.array([[1,2,3], [5,6,7]])
np.concatenate((general,icu), axis = 0)

>> SPLITING
import numpy as np
arr = np.arange(1,11)
arr #run arr
np.array_split(arr,3) #3 is basically number of split in how many part we want to split, it is function to split array, it will split array into equal part


>> ANOTHER WAY TO SPLIT = IT WILL WORK ONLY IF ARRAY HAS NUMBER TO DIVIDE EQUAL
arr2 = np.arange(1,11)
arr2
np.split(arr2,2)  #it will work when equal divisible possible only 

>>ARRAY SORTING
import numpy as np
arr = np.array([1,2,46,7,86])
np.sort(arr)  it will sort array, by default axis will be 0  #row_wise sorting

#coulmn_wise sorting 
import numpy as np
arr = np.array([[1,2,46,7,86], [32,4324,543,4324,4324]]) 
np.sort(arr, axis = 1)
arr

>> Searching = 
import numpy as np
arr3 = np.array([1,2,46,7,86]) 
np.where(arr3>40) #stands for conditional search, it will give u index of that value which is greater than 40


>> np.nonzero(arr) = i will return index of that value whereable u've non zero , basically it will not give u 0 number's index
import numpy as np
arr = np.arange(1,11)
np.nonzero(arr)


>>Filteration = how to filter the data
import numpy as np
arr = np.array([13,5,64,10,78,10])
arr[arr>7]  #it will return element which is greater than 7


>>Mathematical Operations in Numpy

x=np.array([[2,4], [6,10]])
y = np.array([[12,23], [34,8]])
x+y  #======= it will add x +y 









>> x//y = integer division
x=np.array([[2,4], [6,10]])
y = np.array([[12,23], [34,8]])
x//y  #======= it will divide x by y  

>> np.divide(x,y) = float division
import numpy as np
x=np.array([[2,4], [6,10]])
y = np.array([[12,23], [34,8]])
np.divide(x,y)  #=it will give u float division










>> np.multiply(x,y)  #it will multiply


>>matrix = rows multiply by column #condition ye hai = number of column of first array should be equal to the number of second array
arr1 = np.array([[2,4],[1,3]])  
arr2 = np.array([[3,6],[7,3]]) 
np.matmul(x,y) # matmul is function for matrix multiplication, (2×3) + (4×7) = 6 + 28 = 34

>>reshape array = 
#array can be reshape if size before and after reshaping are same
Example: lets suppose I have 14 dimension array, I want to make two dimension array (2,7) but (2,8) isme ham nhi kar skte 
arr = np.arange(1,15)
print(arr)
reshape_array= arr.reshape(2,7) # this is function and shape is 2 and 7, reshape_array this is variable where I'm storing reshaped array
Why?  Two change dimension --- one dimension to 2 dimension 

>>another way to reshape
reshape_array= arr.reshape(2,-1) #basically -1 is only a placeholder it will calculate automatically #automatic dimension calculator 

>>another way to reshape = from 3 dimension to 1 dimension
reshape_array = arr.reshape(-1)  #पूरे array को एक single dimension (1D array) में convert कर दो। , -1 is basically placeholder and arguments


>>Mathematical Operations
1)temp = np.array([23,32,35,54,54])
print(temp)
np.mean(temp) #calculate avg 

2) np.min(temp) #find minimum
(3)np.std(temp) #standard deviation means array के values औसत (mean) से कितना दूर या फैले हुए हैं।

4)np.percentile(temp,40)  #to find percentage
5)np.sum(temp) #to sum
6) np.median(temp) #to find like beech ka number
7)np.prod(temp) #product of all elements product (गुणा)
8)np.cumsum(temp) #cumlative sum  

























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