[BioPython] save or display fasta format

[Brad Chapman]

Hi Sebastian;

> When I parse a FASTA file I get the title and the sequence, and that's 
> OK. But sometimes I want to save a FASTA record to a file or display it 
> in the screen. The problem is that the sequences are printed as one line 
> (it is a string after all).
> I'd like to know if there is an easy way to display them formated (70 
> columns per line for example).

Sure, the standard Fasta.Record class will do this for you:

>>> from Bio import Fasta
>>> my_rec = Fasta.Record()
>>> my_rec.title = "My Record"
>>> print my_rec
>My Record
MEDQVGFGFRPNDEELVGHYLRNKIEGNTSRDVEVAISEVNICSYDPWNLRFQSKYKSRD
AMWYFFSRRENNKGNRQSRTTVSGKWKLTGESVEVKDQWGFCSEGFRGKIGHKRVLVFLD
GRYPDKTKSDWVIHEFHYDLLPEHQ

You can set the number of columns for output when initializing the
record:

my_rec = Fasta.Record(colwidth=30)

To write records to a file, you just need to do:

output_handle.write(str(my_rec) + "\n")

Hope this helps.
Brad