Add Items to a Dictionary

In Python, you can add new items (key-value pairs) to a dictionary in two ways:

• Using square brackets []
• Using the update() method

Example 1: Add Item Using Square Brackets

car = {
 "brand": "Ford",
 "model": "Mustang",
 "year": 1964
}
car["color"] = "Red"
print(car)

Output:

{'brand': 'Ford', 'model': 'Mustang', 'year': 1964, 'color': 'Red'}

Explanation: Since "color" was not a key in the dictionary, it was added with the value "Red".

Example 2: Add Item Using update() Method

car = {
 "brand": "Ford",
 "model": "Mustang",
 "year": 1964
}
car.update({"engine": "V8"})
print(car)

Output:

{'brand': 'Ford', 'model': 'Mustang', 'year': 1964, 'color': 'Red', 'engine': 'V8'}

Explanation: The update() method added the "engine" key with its value to the dictionary.

Example 3: Add Multiple Items at Once

car = {
 "brand": "Ford",
 "model": "Mustang",
 "year": 1964
}
car.update({
 "doors": 2,
 "fuel": "Petrol"
})
print(car)

Output:

{'brand': 'Ford', 'model': 'Mustang', 'year': 1964, 'color': 'Red', 'engine': 'V8', 'doors': 2, 'fuel': 'Petrol'}

Explanation: The update() method can add multiple key-value pairs in a single call by passing another dictionary.

Example 4: Add Item Conditionally

car = {
 "brand": "Ford",
 "model": "Mustang",
 "year": 1964
}
if "owner" not in car:
   car["owner"] = "Alice"
print(car)

Output:

{'brand': 'Ford', 'model': 'Mustang', 'year': 1964, 'color': 'Red', 'engine': 'V8', 'doors': 2, 'fuel': 'Petrol', 'owner': 'Alice'}

Explanation: We added "owner" only if it didn't already exist in the dictionary.

When to Use Which Method?

Conclusion

Adding items to a dictionary in Python is simple and flexible. Use square brackets for quick additions and update() for batch inserts or cleaner code.