“Merging” numpy arrays together with a common dimension [duplicate]

Answer 1

If you can load your data into separate pandas dataframes, this becomes simple.

df

   x  y1
0  0   0
1  1   1
2  2   2
3  3   3
4  4   4
5  5   5

df2

     x   y2
0  0.5  0.5
1  1.5  1.5
2  2.5  2.5
3  3.5  3.5
4  4.5  4.5
5  5.5  5.5

Perform an outer merge, and sort on the x column.

df = df.merge(df2, how='outer').sort_values('x')
df

      x   y1   y2
0     0    0  NaN
6   0.5  NaN  0.5
1     1    1  NaN
7   1.5  NaN  1.5
2     2    2  NaN
8   2.5  NaN  2.5
3     3    3  NaN
9   3.5  NaN  3.5
4     4    4  NaN
10  4.5  NaN  4.5
5     5    5  NaN
11  5.5  NaN  5.5

If you want an array, call .values on the result:

df.values

array([[0.0, 0.0, nan],
       [0.5, nan, 0.5],
       [1.0, 1.0, nan],
       [1.5, nan, 1.5],
       [2.0, 2.0, nan],
       [2.5, nan, 2.5],
       [3.0, 3.0, nan],
       [3.5, nan, 3.5],
       [4.0, 4.0, nan],
       [4.5, nan, 4.5],
       [5.0, 5.0, nan],
       [5.5, nan, 5.5]], dtype=object)