Identifying the first number in a series in the same vector?

I need to identify the first number in a series that is within the same vector such as:

1.97756000000000

1.97784000000000

1.97856000000000

1.97884000000000

1.97912000000000

1.97920000000000

6.28712000000000

6.28968000000000

6.29108000000000

6.29148000000000

6.29180000000000

11.6901600000000

11.6903200000000

11.6904800000000

11.6906400000000

11.6910400000000

16.0839200000000

16.0843600000000

16.0850400000000

16.0852400000000

16.0856800000000

20.4872000000000

20.4883200000000

20.4885600000000

20.4887200000000

I need to list the first 1, 6, 11, 16...etc. Any help is appreciated for this basic question!

Answer 1

[Jon]

define your vector as x then

y = unique(floor(x))

floor gets rid of the decimal part, unique gets rid of the repetitions

[Janet Wallace]

Thank you!