Empty in genebank extractor python code

Question

[MSRS]

I found the gbk extractor python code here (https://github.com/LiguanLi/ARG_MRG_Cooccurrence/blob/master/GBK_CDSextract.py). After a few modifications, the code is as below.

#! /usr/bin/python3

from Bio import SeqIO
from Bio.SeqRecord import SeqRecord
import sys
import getopt

#file_name1=sys.argv[1]
file_name1=input("Enter the full name of genebank file: ")

gb = SeqIO.parse(file_name1, "genbank")
output_handle1=open(file_name1+".ffn","w")
output_handle2=open(file_name1+".faa","w")
output_handle3=open(file_name1+".info.tab","w")

for record in gb:
    print ("Processing GenBank record %s" % record.id)
    for feature in record.features :
        if(feature.type == "source"):
            taxaid = feature.qualifiers['db_xref']
            if len(taxaid) > 1 :
                output_handle3.write("%s\t%s\t%s\t\n" % record.id, record.description, taxaid[1]))
            else:
                output_handle3.write("%s\t%s\t%s\t\n" % record.id, record.description, taxaid[0]))
    for feature in record.features :
        if(feature.type == "CDS"):
            try:
                ID = feature.qualifiers['db_xref'][0]
                desc = feature.qualifiers['protein_id'][0]
                product = feature.qualifiers['product'][0]
                locus = feature.qualifiers['locus_tag'][0]
                nt_seq = feature.extract(record.seq)
                strand=feature.strand
                start=location.start.position
                end=location.end.position
                try:
                        assert len(feature.qualifiers['translation'])==1
                        aa_seq = feature.qualifiers['translation'][0]
                except AssertionError:
                        print (ID,'no amni acids found!')
                        aa_seq=''  
                output_handle1.write(">%s %s %s %s %s %s %s\n%s\n" % (ID, desc, product, locus, strand, start, end, nt_seq))
                output_handle2.write(">%s %s %s %s %s %s %s\n%s\n" % (ID, desc, product, locus, strand, start, end, aa_seq))
            except:
                continue

print ('Retrieving whole genome sequences!')
output_handle1.close()
output_handle2.close()
output_handle3.close()
print ('Done!')

But when I run it, the error message looks like (Solved)

Traceback (most recent call last):
  File "./GBK_CDSextract.py", line 11, in <module>
    gb = SeqIO.parse(file_name1, "genbank")
  File "/home/rahman/.local/lib/python3.8/site-packages/Bio/SeqIO/__init__.py", line 607, in parse
    return iterator_generator(handle)
  File "/home/rahman/.local/lib/python3.8/site-packages/Bio/SeqIO/InsdcIO.py", line 93, in __init__
    super().__init__(source, mode="t", fmt="GenBank")
  File "/home/rahman/.local/lib/python3.8/site-packages/Bio/SeqIO/Interfaces.py", line 47, in __init__
    self.stream = open(source, "r" + mode)
FileNotFoundError: [Errno 2] No such file or directory: ''

I am unable to find out where I need to change. I need help. Thank you.

New error (empty output from the genbank file):

 output_handle1.write(">%s %s %s %s %s %s %s\n%s\n" % (ID, desc, product, locus, strand, start, end, nt_seq))
                    output_handle2.write(">%s %s %s %s %s %s %s\n%s\n" % (ID, desc, product, locus, strand, start, end, aa_seq))

Answer 1

[Mensur Dlakic]

Not sure what is unclear here, as the error message seems pretty obvious:

FileNotFoundError: [Errno 2] No such file or directory: ''

Did you by any chance just hit Enter when being asked for a file name? That would explain the error.

[MSRS]

Thank you very much Dlakic. I have added file name here

file_name1=input("Enter the full name of genebank file: ")

Then getting the error.

[Mensur Dlakic]

Again, the error message is very clear: it can't open a file that is an empty string - that's the meaning of No such file or directory: ''.

When you start the program and get a question Enter the full name of genebank file:, you actually need to type the file name before hitting the Enter key.

[MSRS]

Thank you very much Dlakic. It works now.

But two output files are empty!

output_handle1.write(">%s %s %s %s %s %s %s\n%s\n" % (ID, desc,
    product, locus, strand, start, end, nt_seq))
    output_handle2.write(">%s %s %s %s %s %s %s\n%s\n" % (ID, desc, product, locus, strand, start, end, aa_seq))