Hi,

For image processing, I have to do the following operations :

1/ I have an array and I want to extract every 4 element into another

array :

# r=red, g=green, b=blue, a=alpha

img_data = [ “r1”, “g1”, “b1”, “a1”, "r2, “g2”, “b2”, “a2” ]

=> [ “a1”, “a2” ] # the array of every four elements i.e. alpha data

It’s like extracting the fourth column of a matrix of n rows and 4

columns.

2/ Conversely, I have an array and I need to add elements at every 3

elements

img_data = [ “r1”, “g1”, “b1”, "r2, “g2”, “b2” ]

alpha_data = [ “a1”, “a2” ] # the elements to add

=> [ “r1”, “g1”, “b1”, “a1”, "r2, “g2”, “b2”, “a2” ]

It’s like inserting a column to a matrix of n rows and 3 columns.

I’m wondering if there is an easy or seamless way to do these

operations.

Thanks in advance for any tips.

Cheers.

Chauk-Mean.