Python-Cheatsheet

🔗 Resources / Samples

Data Types

___ i = 5 
___ f = 0.5 
___ b = true
___ c = 'c'
___ s = 'str'
___ arr = [1, 2, 3]

IO Functions

__ ex = input("enter val")
print("You inputted: ", ex)

Control Structure

if (true) {
	print(true)
} else {
	print(false)
}
x = y if true else z

Iterators

for (int i = 0; i < 10; i++) {}
while (i < 10) {}
for val in iterable:

Functions and Methods

def func(param1, param2):
	return param1 + param2
 
# Lambda/anonymous functions
square = lambda x: x*x
 
 
# Method calling syntax
object.method()

File Operations

# Reading
with open("file.txt", "r") as file:
    content = file.read()
 
# Writing
with open("output.txt", "w") as file:
    file.write("Hello world")

Hello World

#optional
def main():
	print("hello")
 
#optional
if __name__ == '__main__':
	main()

int main() {
  std::cout << "Hello, World!" << std::endl;
  return 0;
}

Data Structures and their methods

List / Vector

An array data structure with an O(1) append

list = []
list.append(1)
list.append(2)
list.pop(2)
len(list)
list.map
sort(list)

Stack

A data structure with an O(1) append and pop

For many languages its just a vector

Queue

A FIFO data structure. O(1) append and O(1) pop front

Hash Table

A key-value data structure. O(1) lookup. Known as dict or map usually.

Is there a dedicated set type?

Heap

priority queue

Linked List

Binary Tree

Classes & OOP:

class MyClass:
    # Class variable
    class_var = "I'm shared"
    
    # Constructor
    def __init__(self, param):
        # Instance variable
        self.instance_var = param
    
    # Method
    def my_method(self):
        return self.instance_var
        
# Inheritance
class Child(Parent):
    pass

Error Handling

try:
    risky_operation() # code that might raise an exception
except ExceptionType as e:
    print(f"Error occurred: {e}") # handle specific exception
finally:
    cleanup() # code that runs regardless of exception

Libraries

Importing

How to manage packages

How do I install new ones?
Are there tools to doing it neatly?

Importing in code

# Libraries
import os
from os import *
 
# Modules
from ./utils/mod import database_methods

Critical Libraries:

JSON handling
Timing
File management
Requesting APIs

Concurrency

Command Line Arguments

import sys
args = sys.argv

Vault

Explorer