Updated: 2025-12-28 Sun 19:48

# python-dictionary

planted: 2025-08-05 last tended to: 2025-12-28

Dictionaries are used to store data values in key:value pairs.

A dictionary is a collection which is ordered*, changeable and do not allow duplicates.

*As of Python version 3.7, dictionaries are ordered. In Python 3.6 and earlier, dictionaries are unordered.

Dictionaries are written with curly brackets, and have keys and values:

    # Create and print a dictionary:
      thisdict =	{
        "brand": "Ford",
        "model": "Mustang",
        "year": 1964
      }
      print(thisdict)

Iterating:

Iterate through Value

To iterate through all values of a dictionary in Python using .values(), you can employ a for loop, accessing each value sequentially. This method allows you to process or display each individual value in the dictionary without explicitly referencing the corresponding keys.

Example: In this example, we are using the values() method to print all the values present in the dictionary.

    # create a python dictionary
    d = {"name": "Geeks", "topic": "dict", "task": "iterate"}

    # loop over dict values
    for val in d.values():
        print(val)

Iterate through keys

In Python, just looping through the dictionary provides you its keys. You can also iterate keys of a dictionary using built-in `.keys()` method.

    # create a python dictionary
    d = {"name": "Geeks", "topic": "dict", "task": "iterate"}

    # default loooping gives keys
    for keys in d:
            print(keys)

    # looping through keys
    for keys in d.keys():
            print(keys)

Iterate through both keys and values

You can use the built-in items() method to access both keys and items at the same time. items() method returns the view object that contains the key-value pair as tuples.

    # create a python dictionary
    d = {"name": "Geeks", "topic": "dict", "task": "iterate"}

    # iterating both key and values
    for key, value in d.items():
        print(f"{key}: {value}")

Sorting:

Lambda function accesses the key (item[0]) during sorting. It offers flexibility if you want to tweak the sorting logic later.

    import operator

    a = {"Gfg": 5, "is": 7, "Best": 2, "for": 9, "geeks": 8}
    res = dict(sorted(a.items(), key=lambda item: item[0]))
    print(res)

Explanation: `lambda item: item[0]` sorts the dictionary by the first element of each tuple (the key).

python-sorted-function

python-lambda

Backlinks

- leetcode-arrays