Get the list of index for a string in an array? [duplicate]

Question

I have one array:

string[] cars = {"Volvo", "BMW", "Volvo", "Mazda","BMW","BMW"};

I m looking for the index of BMW, and I using below code to get:

Label1.Text = Array.FindIndex(filterlistinput, x => x.Contains("BMW")).ToString();

Unfortunately it return the result for the first BMW index only. Current output:

 1

My expected output will be

{1,4,5}

Answer 1

You can do something as follows

string[] cars = { "Volvo", "BMW", "Volvo", "Mazda", "BMW", "BMW" };
// Get indices of BMW 
var indicesArray = cars.Select((car, index) => car == "BMW" ? index : -1).Where(i => i != -1).ToArray();
// Display indices
Label1.Text = string.Join(", ", indicesArray);