Question

I am wondering is there way to find out how many pair values(start, end) before I create a new file.txt. My goal here is to check if I start, end value more than one pair then I want to create separate file for each pair. If not then just leave it as is.

def searchPFAM(fname):
    with open(fname,'rb') as f:
        root = etree.parse(f)
        for lcn in root.xpath("/protein/match[@dbname='PFAM']/lcn"):#find dbname =PFAM
            try:
                start = int(lcn.get("start"))#if it is PFAM then look for start value
                end = int(lcn.get("end"))#if it is PFAM then also look for end value
                yield start, end
            except (TypeError , ValueError) as e:
                pass 

with open('newfile.txt','w') as fileinput:
    for start, end in searchPFAM(fname):
        print start, end  
        if start <= end:
            text=''.join(makeList[(start-1):(end-1)])
            fileinput.write(text)

Answer 1

If you want a file for each pair you can do something like this:

for i, (start, end) in enumerate(searchPFAM(fname)):
    print start, end  
    if start <= end:
        with open('newfile-%s.txt' % i,'w') as fileinput:
            text=''.join(makeList[(start-1):(end-1)])
            fileinput.write(text)

Hope this will help.