parsing tabular blast output

Question

[nh75]

Hello to all!

I have seen that Biopython recommend xml output to parse blast file. I need however to do my blast in -outfmt 7

How to parse my file having a tabular output? What I want is to associate queries (end of line) to each organism hits: input

Query= R1_sam10_filt_denovo_18-02-17_c1    cov=4.55 len=204 gc=41.67 nseq=6
ref|XR_001550329.1|  PREDICTED: Oryza brachyantha beta-glucosidas...  53.6    0.002
ref|XR_001550328.1|  PREDICTED: Oryza brachyantha beta-glucosidas...  53.6    0.002
ref|XM_006654251.2|  PREDICTED: Oryza brachyantha beta-glucosidas...  53.6    0.002
ref|XM_006654251.1|  PREDICTED: Oryza brachyantha beta-glucosidas...  53.6    0.002
emb|LN590686.1|  Cyprinus carpio genome assembly common carp geno...  48.2    0.064
Query= R1_sam10_filt_denovo_18-02-17_c2    cov=4.54 len=198 gc=52.78 nseq=6
emb|LN590686.1|  Cyprinus carpio genome assembly common carp geno...  48.2    0.064

output

emb|LN590686.1|  Cyprinus carpio genome assembly common carp geno...   c1     c2
ref|XR_001550329.1|  PREDICTED: Oryza brachyantha beta-glucosidas...   c1

Thanks for your answers!

Answer 1

[Pierre Lindenbaum]

not the output you asked (but anyway, this is a bad output :-) )

$ awk '/^Query=/ {n=split($2,a,/_/);Q=a[n];next;} {print $1,$2, Q;} ' input.blast

ref|XR_001550329.1| PREDICTED: c1
ref|XR_001550328.1| PREDICTED: c1
ref|XM_006654251.2| PREDICTED: c1
ref|XM_006654251.1| PREDICTED: c1
emb|LN590686.1| Cyprinus c1
emb|LN590686.1| Cyprinus c2

[nh75]

thank you very much Pierre!! that's almost what I expected! do you have an idea how to 'merge' the 2 last lines of final output and give them 'c1, c2'? (I already grep the original blast output)

[Pierre Lindenbaum]

sure: a simple awk ,groupby, datamash ...

but it's usually a bad idea to reformat such data.

[nh75]

ok with groupby

bedtools groupby -i output.txt -grp 1 -c 2 -o collapse

what will be the command in awk?

other question related to the output file :

• how to have tabulation between fields?
• how to print query information (cov=4.55 len=204 gc=41.67 nseq=6) into a new file?