Python Cheatsheet
1. VARIABLES & DATA TYPES
x = 10 # Integer
y = 3.14 # Float
name = "Alice" # String
is_valid = True # Boolean
nums = [1, 2, 3] # List
data = (1, 2, 3) # Tuple
info = {"key": "value"} # Dictionary
unique = {1, 2, 3} # Set
2. BASIC OPERATORS
add = 5 + 2 # 7
sub = 5 - 2 # 3
mul = 5 * 2 # 10
div = 5 / 2 # 2.5
floor_div = 5 // 2 # 2
mod = 5 % 2 # 1
power = 2 ** 3 # 8
3. CONDITIONALS
if x > 5:
print("x is large")
elif x == 5:
print("x is 5")
else:
print("x is small")
4. LOOPS
for i in range(5): # 0,1,2,3,4
print(i)
while x > 0:
x -= 1 # Decrease x
5. LIST COMPREHENSION
squared = [i**2 for i in range(5)] # [0, 1, 4, 9, 16]
6. FUNCTIONS
def greet(name="User"):
return f"Hello, {name}!"
print(greet("Bob")) # Hello, Bob!
7. LAMBDA FUNCTION
square = lambda x: x ** 2
print(square(4)) # 16
8. EXCEPTION HANDLING
try:
res = 10 / 0
except ZeroDivisionError:
print("Cannot divide by zero")
9. CLASSES
class Person:
def __init__(self, name):
self.name = name
def say_hello(self):
return f"Hi, I'm {self.name}!"
p = Person("Alice")
print(p.say_hello()) # Hi, I'm Alice!
10. FILE HANDLING
with open("file.txt", "w") as f:
f.write("Hello, World!")
with open("file.txt", "r") as f:
content = f.read()
11. DICTIONARY OPERATIONS
info = {"name": "Alice", "age": 25}
info["city"] = "NY"
print(info.get("name")) # Alice
12. LIST METHODS
nums.append(4) # [1,2,3,4]
nums.remove(2) # [1,3,4]
nums.sort() # [1,3,4]
nums.reverse() # [4,3,1]
13. IMPORTING MODULES
import math
print(math.sqrt(16)) # 4.0
from random import randint
print(randint(1, 10)) # Random number between 1-10
14. ENUMERATE & ZIP
for idx, val in enumerate(["a", "b", "c"]):
print(idx, val) # 0 a, 1 b, 2 c
names = ["Alice", "Bob"]
ages = [25, 30]
for name, age in zip(names, ages):
print(name, age) # Alice 25, Bob 30