I want to reduce a very large dataset with two variables into a smaller file. What I want to do is I need to find the data points with the same values and then I want to keep only the starting and ending values and then remove all the data points in between them. For example the sample dataset looks like following :

363.54167 23.3699
363.58333 23.3699
363.625 0
363.66667 0
363.70833 126.16542
363.75 126.16542
363.79167 126.16542
363.83333 126.16542
363.875 126.16542
363.91667 0
363.95833 0
364 0
364.04167 0
364.08333 0
364.125 0
364.16667 0
364.20833 0
364.25 127.79872
364.29167 127.79872
364.33333 127.79872
364.375 127.79872
364.41667 127.79872
364.45833 127.79872
364.5 0
364.54167 0
364.58333 0
364.625 0
364.66667 0
364.70833 127.43202
364.75 135.44052
364.79167 135.25522
364.83333 135.12892
364.875 20.32986
364.91667 0
364.95833 0
Here, the first two points have same values i.e 26.369 so I will keep them as it is. I need to write a condition i.e if two or more data points have same values then keep only starting and ending data points. Then the next two values also have same value i.e. 0 and i will keep these two. However, after that there are 5 data points with the same values. I need to write a program such that I want to write just two data points i.e 363.708 & 363.875 and remove data points in between them. After that I will keep only two data points with zero values i.e 363.91667 and 364.20833.

The sample output I am looking for is as follows:

363.54167 23.3699
363.58333 23.3699
363.625 0
363.66667 0
363.70833 126.16542
363.875 126.16542
363.91667 0
364.20833 0
364.25 127.79872
364.45833 127.79872
364.5 0
364.66667 0
364.70833 127.43202
364.75 135.44052
364.79167 135.25522
364.83333 135.12892
364.875 20.32986
364.91667 0
364.95833 0