Python — Basic Review before diving deeper 04
Want to recall the memory of Python easily?
This is the note taken while I learned Python “again”, hope it helps you too.
There are additional links in the article for you to understand further information.
Quick tip |
Find ⚡for each topic
☘️Directory
- Exercise 07 — Encryption Program
- Scope
- Tests in W3Schools
❤️Good Resources
Bro code | Python full course
ZeroToMastery | Pyhton
Codes in Github
Encryption Program
Exercise 07 — from Bro Code Tutorials
import random
import string
chars = " " + string.punctuation + string.digits + string.ascii_letters
print(chars)
print("-------------------")
chars = list(chars)
print(chars)
print("-------------------")
Copy the char table and shuffle it to r random one.
key = chars.copy()
print(key)
print("-------------------")
random.shuffle(key)
print(key)
# Encryption
plain_text = input("Enter something to encrypt: ")
cipher_text = ""
for i in plain_text:
index = chars.index(i)
cipher_text += key[index]
print(f"Origin: {plain_text}")
print(f"Encrypted: {cipher_text}")
# Decrypt
encrypted_text = input("Enter the encrypted message: ")
decrypted_text = ""
for i in encrypted_text:
index = key.index(i)
decrypted_text += chars[index]
print(f"Encrypted: {encrypted_text}")
print(f"Origin: {decrypted_text}")
But there is a problem, the encryption table is different every time.
What will you do to solve the problem?
The Whole Code
import random
import string
chars = " " + string.punctuation + string.digits + string.ascii_letters
chars = list(chars)
key = chars.copy()
random.shuffle(key)
# Encryption
plain_text = input("Enter something to encrypt: ")
cipher_text = ""
for i in plain_text:
index = chars.index(i)
cipher_text += key[index]
print(f"Origin: {plain_text}")
print(f"Encrypted: {cipher_text}")
# Decrypt
encrypted_text = input("Enter the encrypted message: ")
decrypted_text = ""
for i in encrypted_text:
index = key.index(i)
decrypted_text += chars[index]
print(f"Encrypted: {encrypted_text}")
print(f"Origin: {decrypted_text}")Scope
🔹What variables do I have access to? — ZTM
🔹A variable is only available from inside the region it is created. This is called scope. — W3Schools
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Scope can generally be divided as four types:
- Local Scope
- Parent Local
- Global Scope
- Built-in Function
🔸Local Scope
# ✅✅✅
def a():
x = 10
print(x)
a()Variable x cannot be called outside of the function a.
# ❌❌❌❌❌
def a():
x = 10
print(x)🔸Parent Local
A.K.A Function in Function
Within the scope the parent function, variable is vailable.
def parent():
x = 10
def child():
print(x)
child()
parent() # 10🔸Global Scope
Can be used in any scopes.
x = 10
def a():
print(x)
print(x) # 10
a() # 10You can change x inside of the function too.
x = 300
def a():
x = 200
print(x)
a()
print(x)🔸Built-in function
x = 5
def parent():
def child():
return sum
return child()
print(parent())
print(x)
🔸Global keyword
If you want to change a global variable in local scope, you can use global keyword.
x = 100
def a():
global x
x = 500
a()
print(x) # 300🔸nonlocal
Used to reference a variable in the nearest scope. — GeeksforGeeks
def a():
x = "John"
def b():
nonlocal x
x = "hello"
b()
return x
print(a())If we didn’t use nonlocal…
def a():
x = "a"
def b():
x = "b"
print('inner', x)
b()
print("outer", x)
a()
