help about the following python script

[sadiexiaoyu]

Hello, everybody,

I would like to run the following python script, but it gives me back error report.

from Bio import SeqIO
out=open("try_out.fasta","w")
for seq_record in SeqIO.parse ("try.fasta","fasta"):
a=seq_record.seq
a=a[5:-6]
id=seq_record.id
out.write(id,a,"fasta")
out.close()

File "try", line 7, in <module>
out.write(id,a,"fasta")
TypeError: function takes exactly 1 argument (3 given)

Could anyone help me about it? I think there might be something wrong with the output file, but I cannot find the solution.

Thanks!

All the best,

Sadiexiaoyu

[finswimmer]

Hello,

File "try", line 7, in <module>
out.write(id,a,"fasta")
TypeError: function takes exactly 1 argument (3 given)

write() expected only one string as parameter. So if you like to write these 3 arguments seperated with comma to the file you can do something like this:

from Bio import SeqIO

out = open("try_out.fasta", "w")
for seq_record in SeqIO.parse("try.fasta", "fasta"):
    a = seq_record.seq
    a = a[5:-6]
    id = seq_record.id
    out.write(id+","+a+","+"fasta"+"\n")
out.close()

The "\n" at the end is neccessary for linebreak, otherwise you would have all entrys in one line.

fin swimmer

[wdecoster]

Now you are writing here a literal "fasta" string on the end of every line. I doubt whether that's what you have in mind. What about this?

from Bio import SeqIO

out = open("try_out.fasta", "a")
for seq_record in SeqIO.parse("try.fasta", "fasta"):
    out.write(seq_record[5:-6].format("fasta"))
out.close()

Note that I changed the "w" in open() to "a" (for append) because you don't want to overwrite the previous record every time again in the loop, right?

[sadiexiaoyu]

hey, there

Hello,

thanks a lot for the reply!

I do it like this now, and it works!

from Bio import SeqIO
out = open('out.fa','w')
for seq_record in SeqIO.parse('original.fa','fasta'):
id = seq_record.id
seq= str(seq_record.seq)[0:-1]
out.write('>'+id+"\n"+seq+'\n')
out.close()

I think the problem is that the seq have to be string instead of characters.
Thanks for the help anyway!

Cheers,

Sadiexiaoyu

[wdecoster]

That's not how you should write fasta output...