Adding and Updating Values

Dictionaries are mutable, meaning you can change their contents after creation. Adding a new key-value pair and updating an existing value use the exact same syntax: assign to the key using bracket notation. Notice that Python doesn't distinguish between adding and updating. If the key exists, the value gets replaced. If the key doesn't exist, it gets created. This is convenient but requires you to be careful about typos. The Typo Trap Because adding and updating use the same syntax, a typo in your key name silently creates a new entry instead of updating the intended one: Fill in the blanks to add a new entry and check how many key-value pairs the dictionary has. Dictionaries are mutable, which means methods and functions can modify them in place. This is both powerful and dangerous. Be a

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