Hello aleksanderczeszyk,

could you please go more into details of what you are trying to do and why?

The aligments within the Blast record objects are in a list. So you can use the slice syntax to truncate them (if this is what you like to do.

from Bio.Blast import NCBIXML

with open("blast.xml") as b:
    for record in NCBIXML.parse(b):
            record.alignments = record.alignments[:50]

fin swimmer