Question

I’m writing a Ruby script to go through a text file and pull the second occurrence of a Regular Expression pattern in each line. Here is an example one line of text:

gi|324021737|ref|NM_001204301.1|    gi|324021738|ref|NP_001191230.1|    100.00  459 0   0   1080    2456    294 752 0.0  905

The number I’m trying to get is the one that is gi|324021738 in the above example, but not the gi|324021737 that comes at the beginning of the line. These values always begin with gi|, but the number of digits following them varies.

What would be the most efficient way to append only the second match to the Regex to an array of strings?

Answer 1

You can use this regex: –

"^gi.*?(gi\|\d+).*?$"

And get the group 1 out of it.