In machine learning projects often we need to create our dataset. As I live in Bangladesh and Bangla is my first language. I faced some issues where I need to convert the numbers while creating a dataset. It is a very simple problem to solve but the main issue is the time complexity. As the now of rows grows it requires more time because of having O(n^2) complexity with a simple procedure of solve. So, Here I tried to solve this with O(n).