example.nf

#!/usr/bin/env nextflow

import static tidynf.TidyMethods.*

tidynf()

workflow.onComplete { println 'done.' }

left = Channel.from([
    ['a', 1, '/file/path/1.bam'],
    ['b', 2, '/file/path/2.bam'],
    ['b', 3, '/file/path/3.bam'],
    ['c', 4, '/file/path/4.bam'],
    ['c', 5, '/file/path/5.bam'],
    ['c', 6, '/file/path/6.bam']])
    .set_names('id', 'value', 'bam')
    .mutate { bam = file(bam) }
    .group_by('id')
    .mutate { n = value.size() }
    .unnest()

right = Channel.from([
    ['a', 'foo'],
    ['b', 'bar'],
    ['c', 'baz'],
    ['d', 'zum']])
    .set_names('id', 'var')

left.inner_join(right, 'id')
    .collect_cols()
    .arrange('id', 'value')
    .unnest()
    .select('id', 'value', 'var', 'n', 'bam')
    .collect_rows()
    .subscribe { println it.collect { it.toString() }.join('\n') }