I’m trying to pass in a “when” block inside a process with a condition of the form: ‘{sample_id}-{taxid}’ in taxid_dict_v2[taxid]. I expect the process to execute for some samples, however the process never executes. When trying to:
println(“Checking if {sample_id}-{taxid} is in ${taxid_dict_v2[taxid]}”) everything looks correct.

A brief reproducible example:
An example when “when” handles a condition correctly:

def taxid_dict_v2 = [
‘3050337’: [‘k10_bird_S5-3050337-megahit-3050337’],
‘694014’: [‘k18_bird_S13-694014-megahit-694014’, ‘k16_bird_S11-694014-megahit-694014’, ‘k24_bird_S19-694014-megahit-694014’],
]
params.taxid_dict_v2 = taxid_dict_v2

params.taxid = [‘3050337’, ‘694014’]

process EXTRACT_KRAKEN_READS_FASTA {
input:
tuple val(sample_id), val(reads)
val(taxid_dict_v2)
each taxid

when:
sample_id in taxid_dict_v2[taxid]

output:
val sample_id

script: 
"""
echo ${sample_id}
"""
}
workflow {
taxid_dict_v2 = params.taxid_dict_v2
taxid = params.taxid
samples = Channel.of( [‘k10_bird_S5-3050337-megahit-3050337’, ‘1’], [‘k18_bird_S13-694014-megahit-694014’, ‘2’], [‘k24_bird_S19-694014-megahit-694014’, ‘3’] )

EXTRACT_KRAKEN_READS_FASTA(samples , taxid_dict_v2, taxid).view()
}

An example when “when” handles a condition incorrectly

process EXTRACT_KRAKEN_READS_FASTA {
input:
tuple val(sample_id), val(reads)
val(taxid_dict_v2)
each taxid

when:
"${sample_id}-${taxid}" in taxid_dict_v2[taxid]

output:
val sample_id

script: 
"""
echo ${sample_id}
"""
}
workflow {
taxid_dict_v2 = params.taxid_dict_v2
taxid = params.taxid
samples = Channel.of( [‘k10_bird_S5-3050337-megahit’, ‘1’], [‘k18_bird_S13-694014-megahit’, ‘2’], [‘k24_bird_S19-694014-megahit’, ‘3’] )

EXTRACT_KRAKEN_READS_FASTA(samples, taxid_dict_v2, taxid).view()
}