Default split not appropriate.

smwrappers/explore_mapping_parameters/wrapper.py

@@ -54,6 +54,11 @@ echo -e "${{rate}}\\t{snakemake.params.these_settings}" >> {snakemake.params.rat
         return run_with_modules(shell_commands, modules)
     return shell_commands
 
+
+def split_on_tab(s):
+    return s.split("\t")
+
+
 with NamedTemporaryFile() as fastq, NamedTemporaryFile() as rates_record:
     snakemake.params.fastq = fastq.name
     # Take the first 10000 reads from the input
@@ -67,7 +72,7 @@ with NamedTemporaryFile() as fastq, NamedTemporaryFile() as rates_record:
     (best_rate, best_settings) = max(
         (float(rate), settings)
         for (rate, settings)
-        in map(bytes.split, rates_record))
+        in map(split_on_tab, rates_record))
     with open(snakemake.output.mapping_params, "w") as fh:
         fh.write(f"{best_params}\t({best_rate}%%)\n")