How to only keep data surrounding a line/column intersection in Pandas Data frame?

If I have an array with column indices for each row like this:

 array = [NaN, 3, 4, 3, NaN]

And a pandas data frame like this:

     1   2   3   4   5   6
 1   1  NaN NaN NaN NaN  1
 2   1   1   1  NaN NaN  1
 3  NaN  1   1   1   1   1 
 4  NaN  1   1   1  NaN  1
 5   1  NaN  1  NaN NaN  1

How do I keep values that overlap with my column index for each row such that I get a data frame like this:

      1   2   3   4   5   6
 1   NaN NaN NaN NaN NaN NaN
 2    1   1   1  NaN NaN NaN
 3   NaN  1   1   1   1   1 
 4   NaN  1   1   1  NaN NaN
 5   NaN NaN NaN NaN NaN NaN

Where data associated with my rows column index is preserved? Basically, I want to only keep data that intersects and is surrounded by my column index.

from How to only keep data surrounding a line/column intersection in Pandas Data frame?