Python Basics Cheat Sheet

Python Cheatsheet

Basics

# Print Statement
print("Hello, World!")

# Variables
x = 5
y = "Hello"

# Data Types
int_var = 10            # Integer
float_var = 10.5        # Float
str_var = "Hello"       # String
bool_var = True         # Boolean
list_var = [1, 2, 3]    # List
tuple_var = (1, 2, 3)   # Tuple
set_var = {1, 2, 3}     # Set
dict_var = {"key": "value"}  # Dictionary

Control Structures

# If-Else
if x > 0:
    print("Positive")
elif x == 0:
    print("Zero")
else:
    print("Negative")

# For Loop
for i in range(5):
    print(i)

# While Loop
count = 0
while count < 5:
    print(count)
    count += 1

Functions

def my_function(param1, param2):
    return param1 + param2

result = my_function(5, 3)
print(result)

Classes

class MyClass:
    def __init__(self, name):
        self.name = name

    def greet(self):
        return f"Hello, {self.name}!"

obj = MyClass("Harlin")
print(obj.greet())

Exception Handling

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero!")
finally:
    print("Execution complete.")

File Operations

# Read from a file
with open('file.txt', 'r') as file:
    content = file.read()
    print(content)

# Write to a file
with open('file.txt', 'w') as file:
    file.write("Hello, World!")

List Comprehensions

# Basic List Comprehension
squares = [x**2 for x in range(10)]
print(squares)

# Conditional List Comprehension
evens = [x for x in range(10) if x % 2 == 0]
print(evens)

Lambda Functions

# Lambda Function
add = lambda a, b: a + b
print(add(5, 3))

Map, Filter, Reduce

from functools import reduce

# Map
numbers = [1, 2, 3, 4, 5]
squared = list(map(lambda x: x**2, numbers))
print(squared)

# Filter
evens = list(filter(lambda x: x % 2 == 0, numbers))
print(evens)

# Reduce
sum_numbers = reduce(lambda a, b: a + b, numbers)
print(sum_numbers)

Modules

# Importing a Module
import math
print(math.sqrt(16))

# Importing Specific Functions
from math import pi, sin
print(pi)
print(sin(0))

Numpy Basics

import numpy as np

# Creating Arrays
arr = np.array([1, 2, 3, 4, 5])
print(arr)

# Array Operations
print(arr + 5)
print(arr * 2)
print(np.sqrt(arr))

Pandas Basics

import pandas as pd

# Creating DataFrame
data = {
    'Name': ['Alice', 'Bob', 'Charlie'],
    'Age': [24, 27, 22]
}
df = pd.DataFrame(data)
print(df)

# Basic Operations
print(df['Name'])
print(df.describe())
print(df[df['Age'] > 23])

Matplotlib Basics

import matplotlib.pyplot as plt

# Basic Plot
x = [1, 2, 3, 4, 5]
y = [2, 3, 5, 7, 11]
plt.plot(x, y)
plt.xlabel('x-axis')
plt.ylabel('y-axis')
plt.title('Sample Plot')
plt.show()