📘 Python Dictionary Cheat Sheet

🔧 Creating Dictionaries

my_dict = {"name": "Alice", "age": 25, "city": "New York"}
empty_dict = {}
alt_dict = dict(name="Bob", age=30)

🛠 Accessing Values

my_dict["name"]            # Get value by key
my_dict.get("age")         # Get with default fallback

➕ Adding / Updating Items

my_dict["email"] = "alice@example.com"  # Add new key-value
my_dict["age"] = 26                     # Update value
my_dict.update({"city": "Boston", "job": "Engineer"})  # Multiple updates

➖ Removing Items

my_dict.pop("age")         # Remove by key
del my_dict["city"]        # Delete key
my_dict.popitem()          # Remove last inserted item
my_dict.clear()            # Remove all items

🔁 Looping Through Dictionary

for key in my_dict:
    print(key, my_dict[key])
for key, value in my_dict.items():
print(key, value)

🔍 Checking Keys

"name" in my_dict          # Check if key exists
"email" not in my_dict      # Check if key does NOT exist

📋 Dictionary Methods

my_dict.keys()              # Get all keys
my_dict.values()            # Get all values
my_dict.items()             # Get key-value pairs

🧱 Dictionary Comprehension

squares = {x: x*x for x in range(5)}  # {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

🧪 Copying a Dictionary

new_dict = my_dict.copy()    # Shallow copy
new_dict = dict(my_dict)     # Another way

⚙️ Merging Dictionaries (Python 3.9+)

dict1 = {"a": 1}
dict2 = {"b": 2}
merged = dict1 | dict2       # Combine dictionaries