[Pytables-users] subarray extraction and update

[Bernard K. <ber...@be...>]

Dear all,

I am using pytables mostly to store data in the form of simple 
two-dimensional arrays. For my calculations I often need to extract and 
update submatrices of these arrays. Unfortunately the row and column 
indexes I am using can not be described as slices because those can be 
quite random.

Can anyone teach me a "good" (meaning memory efficient, fast and 
elegant) way to code submatrix extraction and update ?
The ideal for me would be a code close to this one :

x=array([1,2,5,8])   # row index
y=array([0,3,7])   # column index
a=data[x,y]   # returns an array of size [4,3], 'data' is a pytables 2-d 
array
data[x,y]=0   # set the submatrix defined by x rows and y columns to 0
data[x,y]=rand([4,3])  # update of a submatrix
data[x,y]=data2[x,y]   # copy of a submatrix from one array into another

Sincerely,

Bernard KAPLAN