How to do this type of insert in 2d array in python?

Question

I have 2D array where y is sorted and unique.so insert operation should be based on y.

x	y
0.012	396.470
0.017	401.480
0.028	406.490
0.032	411.500
0.038	416.510
0.043	421.520
0.046	426.530
0.051	431.540
0.050	436.540
0.050	441.550

 and now i have another inputed2darray

0.030	408.505
0.043	421.520
0.050	430.050
0.047	438.540

then output array should be like this

x	y
0.012	396.470
0.017	410.480
0.028	406.490
0.030	408.505
0.032	411.500
0.038	416.510
0.043	421.520
0.046	426.530
0.050	430.050
0.051	431.540
0.050	436.540
0.047	438.540
0.050	441.550

 

 and also return the index of inserted and non inserted(if the element is present in the list then not insert) element

 outputindexarr=[3,6,8,11] 

 yellow highlighted:was not present in the given 2d array so it was inserted in the outputarray

green highlighted: was present in the given 2d array so it was inserted in the outputarray.