What Is a Dictionary?

A Python dictionary stores values in key → value pairs. It’s one of the most important and most used data types in Python.

person = {
    "name": "Kaloyan",
    "age": 12,
    "country": "Bulgaria"
}
      

Accessing Values

print(person["name"])     # Kaloyan
print(person["age"])      # 12
      

Adding and Changing Values

person["age"] = 13
person["city"] = "Sofia"
      

Removing Keys

del person["city"]
      

Looping Through a Dictionary

Keys Only

for key in person:
    print(key)
      

Keys and Values

for key, value in person.items():
    print(key, "=", value)
      

Check If a Key Exists

if "name" in person:
    print("Name exists!")
      

Dictionary Length

print(len(person))
      

Nested Dictionaries

students = {
    "kal": {"age": 12, "grade": 6},
    "ivo": {"age": 13, "grade": 7}
}

print(students["kal"]["grade"])
      

When to Use Dictionaries?

• Storing structured data
• Fast lookup using keys
• Configs, settings, JSON, APIs
• User accounts, profiles, metadata

Full Example — User Profile

user = {
    "username": "CodeTweakrs",
    "premium": False,
    "projects": ["SysDash", "SysTweak", "CT-Cleaner"]
}

print("User:", user["username"])
print("Projects:", ", ".join(user["projects"]))
      

What’s Next?

Next you’ll learn about HTML semantic tags — the proper way to structure web pages for clarity, SEO, and accessibility.