First Unique Character using Python

The problem of finding the first unique character in a string is a popular coding interview question. Here you will be given a string, and you have to return the index of the first non-repeating character in the string as an output. So, if you want to know how to find the first unique character in a string, this article is for you. In this article, I will take you through how to find the first unique character in a string using Python.

First Unique Character in a String

In the problem of finding the first unique character in a string, you will be given a string as input. To solve this problem, you need to find the index of the first character in the string that is non-repeating in the string. And if there is no unique character, your output should return -1.

For example, look at the input and output of this problem shown below:

  • Input: “amankharwal” | Output: 1 (index of m)
  • Input: “aamm” | Output: -1 (no unique character found)

Finding the First Unique Character using Python

I hope you have understood what the problem of finding the first unique character in a string means. Now, below is how you can solve this problem using the Python programming language:

def firstUniqueChar(s):
    from collections import Counter
    count = Counter(s)
    for i , j in enumerate(s):
        if count[j] == 1:
            return i
    else:
        return -1

print(firstUniqueChar("amankharwal"))
Output: 1

So this is how you can find the first unique character in a string using Python. You can find many more practice questions for coding interviews solved and explained using Python here.

Summary

In the problem of finding the first unique character in a string, you will be given a string as input. To solve this problem, you need to find the index of the first character in the string that is non-repeating in the string. I hope you liked this article on finding the first unique character in a string using Python. Feel free to ask valuable questions in the comments section below.

Aman Kharwal
Aman Kharwal

I'm a writer and data scientist on a mission to educate others about the incredible power of data📈.

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