python - IndexError: list index out of range, but each string can be printed out -

i writing script pool lines filea when first 2 columns same fileb. filea txt file 3 column separated tab, , fileb txt file 2 column separated tab. keeps showing error following: "site=a[0]+’\t’+a[1] indexerror: list index out of range" can print a[0], a[1], a[2] , site.

here code:

fileb=open('atog_mock.txt').readlines() filea=open('depth_ice.txt').readlines() outfile=open('atog_depth_ice.txt','w') dict1={}  line in filea:     a=line.strip().split('\t')     site = a[0]+' '+a[1]     if site not in dict1:         dict1[site]=a[2]  line in fileb:     b=line.strip().split('\t')     site=b[0]+' '+b[1]     if site in dict1:         outfile.write(b[0]+'\t'+b[1]+'\t'+dict1[site]+'\n')  outfile.close() 

i appreciate help!

we can't give definitive answer because don't have access data files, can debug wrapping problematic line in try/except block:

try:     site = a[0]+' '+a[1] except indexerror:     print("error: is", a)     raise 

most there's empty line somewhere, last line.