Question

I am trying to implement substitution in perl.
I have a binary matrix and I would like to replace

0 with 1

and

1 with 2.

So i used the following line

s/1/2/g foreach @remaining;

However, this command ends up replacing my column names as well which has numbers in it. it converts, for example, 1234 to 2234.

I want it to match and replace only 1s and not 1234.

Answer 1

Use word boundaries like:

s/\b1\b/2/g foreach @remaining;

To replace 0 and 1 at the same time:

s/\b([01])\b/1+$1/eg foreach @remaining;