How To Get First Key Value Pair in Dictionary Python?

In Python, dictionaries are unordered until Python 3.7 and ordered by insertion order from Python 3.7 onwards. To get the first key-value pair from a dictionary, you can use various methods. Here are some common approaches:

1. Using next() and iter():

This is a concise way to get the first key-value pair from a dictionary. It works in both Python 2 and Python 3.

my_dict = {'a': 1, 'b': 2, 'c': 3}
first_pair = next(iter(my_dict.items()))
# first_pair is ('a', 1)

2. List Conversion:

Convert the dictionary items to a list and then access the first element. This is not the most efficient method but is straightforward.

my_dict = {'a': 1, 'b': 2, 'c': 3}
first_pair = list(my_dict.items())[0]
# first_pair is ('a', 1)

3. Using a Loop:

Though not efficient for just accessing the first element, a loop can be used to get the first key-value pair. The loop will break after the first iteration.

my_dict = {'a': 1, 'b': 2, 'c': 3}
for first_pair in my_dict.items():
    break
# first_pair is ('a', 1)

4. Unpacking in a For Loop:

Similar to the above, but unpacks the key and value during iteration.

my_dict = {'a': 1, 'b': 2, 'c': 3}
for key, value in my_dict.items():
    first_key, first_value = key, value
    break
# first_key is 'a', first_value is 1

5. Using keys() and values() Methods:

If you need the key and value separately, you can use these methods. This is less efficient than the iter() method.

my_dict = {'a': 1, 'b': 2, 'c': 3}
first_key = next(iter(my_dict.keys()))
first_value = my_dict[first_key]
# first_key is 'a', first_value is 1

Each method can be suitable depending on your specific use case and the version of Python you are using. The next() and iter() method is generally the most efficient and Pythonic way to achieve this in modern Python versions.