by arg of join operator do not work

[Benoitdw]

Bug report

The by argument of the join operator do not work

Expected behavior and actual behavior

left = Channel.of([1, 'Z'], [5, 'Y'], [1, 'X'])
right = Channel.of(['Z', 6], ['Y', 5], ['X', 4])

left.join(right, by: [1, 0]).view()

I expect to have:

[1,'Z',6], [5,'Y',5], [1, 'X', 4]

But I have no output

Environment

• Nextflow version: [24.10.4]
• Java version: 17.0.10
• Operating system: Linux
• Bash version: (use the command $SHELL --version) : ZSH 5.9

[bentsherman]

I assume you are trying to join by index 1 on the left and index 0 on the right. But that is not possible using the by option alone. What you have done is to join on index 1 and 0 from both sides, which in this case yields no matches.

Try this instead:

left = Channel.of([1, 'Z'], [5, 'Y'], [1, 'X'])
right = Channel.of(['Z', 6], ['Y', 5], ['X', 4])

left
  .map { a, b -> [b, a] }
  .join(right)
  .view()