Get First Index of List in Python (3 Examples)

In this tutorial, you’ll learn how to get the first index of a list in the Python language.

The content of the tutorial is structured as follows:

1) Create Example Data

2) Example 1: Get First Element of List Using Indices

3) Example 2: Get First Index of List Using index() Function

4) Example 3: Get First Index of List Using for Loop

5) Example 4: Get First Index of List Using List Comprehension

6) Video, Further Resources & Summary

Let’s go straight to the code!

Create Example Data

As the first step, we will create a sample string list named my_list to use in the following examples.

my_list = ['a', 'b', 'c', 'd', 'e']
print(my_list)
# ['a', 'b', 'c', 'd', 'e']

Let’s see how to retrieve the first index in our list!

Example 1: Get First Element of List Using Indices

Before getting into how to get the first index in my_list, it might be interesting to know how to get the first element in this list. The first index in my_list can be found as follows.

first_element = my_list[0]
print(first_element)
# a

As you can see, my_list[0] contains the first element in our list. Now we know that the first element in my_list is ‘a’, we can use this information to return the index number at this position as well.

In our simplified example, we know that this index number is 0. However, sometimes we might not know the index number that corresponds to a certain element. In these cases, the following code might be useful, so keep on reading!

Example 2: Get First Index of List Using index() Function

We can get the index of the first element in our list using the index() function.

first_index = my_list.index('a')
print(first_index)
# 0

As you can see, my_list.index('a') returns the index of the first element ‘a’ in my_list, which is 0.

Example 3: Get First Index of List Using for Loop

Using a for loop is another way to get the index of the first element in my_list. Let’s take a look!

for i in range(len(my_list)):
    if my_list[i] == 'a':
        first_index = i
        break
print(first_index)
# 0

In this example, the for loop iterates over each index in the list using the range of the length of the list, and checks if the element at that index is equal to ‘a’. When it finds ‘a’, it assigns the index to first_index and breaks out of the loop.

Example 4: Get First Index of List Using List Comprehension

Using list comprehension can also be handy if you want to print the index of the first element.

first_index = [i for i in range(len(my_list)) if my_list[i] == 'a'][0]
print(first_index)
# 0

This code finds the first occurrence of ‘a’ in my_list and prints its index. If there is no ‘a’ in the list, it will raise an IndexError since the list comprehension will be an empty list, and it’s trying to access the first element of it.

Video, Further Resources & Summary

Do you need more explanations on how to get the first index in a list in Python? Then you should have a look at the following YouTube video of the Statistics Globe YouTube channel.

The YouTube video will be added soon.

Furthermore, you may want to have a look at some other articles on Statistics Globe:

This post has shown how to get the first index of a list in Python. If you have further questions, please let me know in the comments section.

Paula Villasante Soriano Statistician & R Programmer

This page was created in collaboration with Paula Villasante Soriano. Please have a look at Paula’s author page to get further information about her academic background and the other articles she has written for Statistics Globe.