Python – Count Keys in a Dictionary

In this tutorial, we will look at how to count the number of keys in a Python dictionary with the help of some examples.

How to count the number of keys in a dictionary in Python?

You can use the Python built-in len() function to count the number of keys in a dictionary. Pass the dictionary as an argument. The following is the syntax:

# count keys in dictionary d
len(d)

It returns the count of keys in the dictionary, which is the same as the length of the dictionary.

Let’s look at some examples.

Using len() function

You can apply the len() function directly on the dictionary to get the number of keys in the dictionary.

# create a dictionary
employees = {
    "Jim": "Sales",
    "Dwight": "Sales",
    "Angela": "Accounting"
}
# count keys in the dictionary
print(len(employees))

Output:

3

We find that the dictionary in this example has three keys, which is correct.

You can get the keys in a dictionary as an iterable using the dictionary’s keys() method. If you apply the len() function to the resulting iterable (which is a dict_keys object), you can get the count of the keys in the dictionary.

# count keys in the dictionary
print(len(employees.keys()))

Output:

3

We get the same result as above.

Using iteration

A naive way of counting the keys in a dictionary could be to iterate through the dictionary and count its keys using an additional variable.

Here’s an example.

# create a dictionary
employees = {
    "Jim": "Sales",
    "Dwight": "Sales",
    "Angela": "Accounting"
}
# count keys in the dictionary
count = 0
for key in employees:
    count += 1
print(count)

Output:

3

Here we iterate over each key in the dictionary and increase the counter by one in each iteration. We get the same result as the above methods.

In this tutorial, we looked at some methods to get a count of keys in a dictionary. Using the len() function is simple and straightforward compared to the iteration method.

You might also be interested in –

1. Check If a Python Dictionary Contains a Specific Key
2. Check If a Dictionary Is Empty In Python
3. Python view dictionary Keys and Values