Python

Python Dictionary Methods

Python provides several built-in dictionary methods that allow you to efficiently manipulate, access, and transform dictionary data. Here is a list of some important dictionary methods in Python:

Method	Description
`dict.clear()`	Removes all items from the dictionary
`dict.copy()`	Returns a shallow copy of dictionary `dict`
`dict.fromkeys()`	Creates a new dictionary with keys from the given sequence
`dict.get(key, default=None)`	For key `key`, returns value or `default` if key not in dictionary
`dict.items()`	Returns a new view containing a tuple for each key value pair
`dict.keys()`	Returns a view object that displays a list of all the keys in the dictionary
`dict.values()`	Returns a view object containing all dictionary values, which can be accessed and iterated through efficiently
`dict.setdefault(key, default)`	Returns the value of a key if the key is in the dictionary else inserts the key with a value to the dictionary
`dict.update(other)`	Updates the dictionary with the elements from another dictionary or an iterable of key-value pairs. With this method, you can include new data or merge it with existing dictionary entries
`dict.pop()`	Returns and removes the element with the given key
`dict.popitem()`	Returns and removes the item that was last inserted into the dictionary
`dict.has_key(key)`	`has_key()` method was removed in Python 3. Use the in operator instead

Built-in Functions with Dictionaries

Following are the built-in functions we can use with Dictionaries.

Function	Description
`dict()`	Creates a new dictionary
`len(dict)`	Gives the total length of the dictionary. This would be equal to the number of items in the dictionary
`str(dict)`	Produces a printable string representation of a dictionary
`type(variable)`	Returns the type of the passed variable. If passed variable is dictionary, then it would return a dictionary type
`isinstance(dict)`	Checks if an object is a dictionary. Remember that custom dictionary subclasses will also return True.
`list(dict)`	Converts dictionary keys to a list
`sorted(dict)`	Returns a new sorted list of dictionary keys. Remember that `sorted()` returns a list, not a dictionary. If you need a sorted dictionary, you'll need to create a new one from the sorted items.
`tuple(dict)`	Converts dictionary keys to a tuple
`tuple(dict.values())`	Converts dictionary values to a tuple
`iter(dict)`	Return an iterator over the keys of the dictionary. This is a shortcut for `iter(dict.keys())`
`iter(dict.values())`	Return an iterator over all values in a dictionary
`reversed(dict)`	Return a reverse iterator over the keys of the dictionary. This is a shortcut for `reversed(dict.keys())`
`sum(dict)`	Sums dictionary keys (if they're numbers)
`max(dict)`	Find maximum keys
`min(dict)`	Find minimum keys
`sum(dict.values())`	Sums dictionary values (if they're numbers)
`max(dict.values())`	Find maximum values
`min(dict.values())`	Find minimum values

FAQs on Python Dictionary Methods

What’s the difference between `clear()` and reassigning `{}`?

my_dict.clear() removes all items from the existing object. Reassigning my_dict = {} creates a new empty dictionary, which may not update other references to the original dictionary.

How can I check if a key exists in a dictionary?

You can use the in operator

my_dict = {'name': 'John'}
if 'name' in my_dict:
    print("Key exists!")

How do I remove a specific key-value pair from a dictionary?

You can use either the pop() method to remove and return the value, or del statement:

my_dict = {'a': 1, 'b': 2}
value = my_dict.pop('a')  # Removes 'a' and returns 1
del my_dict['b']          # Removes 'b'