Fill array between values

I have an array like this.

0 0 0 0 0 0 1 0 0 0 0 0 2 0 0 0 0 0 0 0

0 0 0 0 0 1 0 0 1 0 0 2 0 2 0 0 0 0 0 0

0 0 0 0 0 0 1 0 2 0 1 0 2 0 0 0 0 0 0 0

I'd like to fill 3 between 1 and 2, like this.

0 0 0 0 0 0 1 3 3 3 3 3 2 0 0 0 0 0 0 0

0 0 0 0 0 1 3 3 1 3 3 2 3 2 0 0 0 0 0 0

0 0 0 0 0 0 1 3 2 0 1 3 2 0 0 0 0 0 0 0

Is there any way to solve this?

I can't find function to do so.

Answer 1

[Chunru]

The rule is not clear in your question. In first/second row, you fill 3 between first 1 and last 2. In third row, you fille 3 between 2 pairs of 1 and 2.

The code below assume the rule is to fill 3 between 1st 1 and last 2. You can change the code to fit the rule you set.

A =[0 0 0 0 0 0 1 0 0 0 0 0 2 0 0 0 0 0 0 0 
    0 0 0 0 0 1 0 0 1 0 0 2 0 2 0 0 0 0 0 0 
    0 0 0 0 0 0 1 0 2 0 1 0 2 0 0 0 0 0 0 0];
for i=1:size(A,1)
    i1 = find(A(i,:)==1, 1, 'first');
    i2 = find(A(i,:)==2, 1, 'last');
    i0 = find(A(i,i1:i2) == 0);
    A(i, i1-1 + i0) = 3;
end
A

A = 3×20

0 0 0 0 0 0 1 3 3 3 3 3 2 0 0 0 0 0 0 0 0 0 0 0 0 1 3 3 1 3 3 2 3 2 0 0 0 0 0 0 0 0 0 0 0 0 1 3 2 3 1 3 2 0 0 0 0 0 0 0

[J PARK]

Sorry for bad expression.

My intension was filling pairs of 1 and 2.

I'll review your code.

Thanks!

[Chunru]

Then in second row, you have nested pair.

[J PARK]

Umm..

If 1 or 2 duplicates, I want to use first 1 and last 2.