Get the First Key in Dictionary - Python

We are given a dictionary and our task is to find the first key in the dictionary. Since dictionaries in Python 3.7+ maintain insertion order, the first key is the one that was added first to the dictionary. For example, if we have the dictionary {'a': 10, 'b': 20, 'c': 30}, the first key is 'a'.

Using next() with iter()

We use iter() to get an iterator over the dictionary and next() to retrieve the first element from the iterator, which gives us the first key.

d = {'harsh': 40, 'aryan': 10, 'kunal': 30}
res = next(iter(d))
print(res)

harsh

Explanation:

• iter() function returns an iterator object for the dictionary.
• next() function retrieves the first item from the iterator which is the first key in the dictionary.

Using list() Conversion

We convert the dictionary keys into a list using list() and then access the first element of the list which gives us the first key.

d = {'harsh': 40, 'aryan': 10, 'kunal': 30}
res = list(d)[0]
print(res)

harsh

Explanation: list() function converts the dictionary keys into a list and then we access the first element of the list using index 0 which corresponds to the first key in the dictionary.

Using a Loop

We use a loop to iterate over the dictionary's keys, breaking after the first iteration to get the first key.

d = {'harsh': 40, 'aryan': 10, 'kunal': 30}
for k in d:
    res = k
    break
print(res)

harsh

Explanation: We start looping through the dictionary and in the first iteration we assign the key to res and break out of the loop immediately.