Example: Index.of Lollita Is There A MATLAB Function That Can Find The Index Of A Specified Double In A Vector?

Is there a MATLAB function that can find the index of a specified double in a vector? - example: index.of lollita

For example:

vector = [10, 20, 30, 40, 50]
findfunction a = (vector 40)
a = 4

Is there findfunction so?