Find the first and last element of the array that are equal or larger than a value without sorting?

Question

Import numpy as np
a = np.array([2, 1 , 3 , 6, 4, 3, 6,1])

I want to find the first number that is equal or larger than 3 and the last number that is equal or larger than 3 without sorting.

Answer 1

With a for loop