write fastq with Python

[neni]

Hello. My problem seems so super basic, I haven't found an answer in this forum... I'm really brand new in this field..

I want to convert a .sff into a .fastq according the Biopython manual:

>>> from Bio import SeqIO
>>> from StringIO import StringIO
>>> out_handle = StringIO()
>>> count = SeqIO.convert("c:HPISTN001.sff", "sff",
... out_handle, "fastq")

But how do i GET the .fastq file, stored on c:?

[maubp]

You've asked Biopython to write the FASTQ file to a string in memory, actually a special object called StringIO which mimics a file in memory.

All you need to do is this:

from Bio import SeqIO
count = SeqIO.convert(r"c:\HPISTN001.sff", "sff", r"C:\HPSITN001.fastq", "fastq")
print "Converted %i records" % count

Also note the use of r"xxxxx" to mean a raw string where \ is just a slash. Otherwise by default Python treats \n as a new line, and \t as a tab etc - which can be unhelpful with Windows style paths.

Which bit of the tutorial did you find unclear? I'd like to clarify it if possible.

[kopardev]

Sff_extract.py script