Suppose we have the following list
data = {{0,1},{-1,2},{5,-2},{4,4},{3,0},{-1,1},{6,0.5},{7,2},{8,-5},{9,2}}
How can we remove all elements of this list which have the same x value? For example, in the above example, the entries {-1,2} and {-1,1} should be removed, since in both of them the x value is the same (-1).
I tried DeleteDuplicates[data]
but it does not work.
Many thanks in advance and Merry Christmas to all!