Question

My source file is tab delimited and I need to grep the 4th column of values. How can I do this in Groovy? Here’s my code which doesn’t work. Is it even close?

 def tab_file = new File('source_file.tab')
 tab_file.eachline { line -> println line.grep('\t\t\t\t'} 

Answer 1

You could split by tab character, that would give you an array you can index into to get the column:

groovy:000> s = "aaa\tbbb\tccc\tddd\teee";
===> aaa        bbb     ccc     ddd     eee
groovy:000> s.split("\\t")[3]
===> ddd