Accessing Dictionary Values

Once you have a dictionary, you need to get values out of it. Unlike lists where you use numeric indexes, dictionaries use keys.

Reading Values

Use square brackets with the key name:

person = {"name": "Alice", "age": 30}

print(person["name"])  # Alice
print(person["age"])   # 30

This looks similar to list indexing, but instead of a number, you provide the key string.

If you try to access a key that isn't in the dictionary, Python raises a KeyError:

person = {"name": "Alice", "age": 30}
print(person["email"])  # KeyError: 'email'

This crashes your program unless you handle the error.

The get() method provides a safer alternative. If the key doesn't exist, it returns None instead of crashing:

person = {"name": "Alice", "age": 30}

print(person.get("email"))  # None (no error)

You can also provide a default value:

print(person.get("email", "N/A"))  # N/A

This is perfect when you're not sure if a key exists and want to handle missing data gracefully.

To change an existing value, assign to its key:

person = {"name": "Alice", "age": 30}
person["age"] = 31
print(person)  # {'name': 'Alice', 'age': 31}

Adding a new key-value pair uses the same syntax:

person = {"name": "Alice", "age": 30}
person["city"] = "Boston"
print(person)  # {'name': 'Alice', 'age': 30, 'city': 'Boston'}

If the key exists, it updates. If it doesn't, it adds.

Use the in operator to check before accessing:

person = {"name": "Alice", "age": 30}

if "email" in person:
    print(person["email"])
else:
    print("No email on file")

Use del to remove a key-value pair:

person = {"name": "Alice", "age": 30, "city": "Boston"}
del person["city"]
print(person)  # {'name': 'Alice', 'age': 30}

Or use pop() to remove and get the value:

city = person.pop("city")  # Returns "Boston" and removes the key