Python read lines from a file and write from a specific line number to another file

Question

I want to read the lines from a file and write from a specific line number to another file. I have this script, which writes all the read lines. I need to skip the first four lines and write the rest to another fils. Any ideas?

for k in range (0,16):
    print 'k =',k
    from  abaqus import session
    k=k+1
    print k 
    f1 = open('VY_NM_VR_lin_o1_bonded_results_{k}.txt'.format(k=k))
    #with open('VY_{k}'.format(k=k), 'a') as f1:
    lines = f1.readlines()
    for i, line in enumerate(lines):
        #print i    
        print(repr(line))               
        #if line.startswith(searchquery):
        f2.write(line)
        #f2.write('%s'%listc + "\n")
        i = i+1
        #else :
        #    i = i+1
        #os.close(f1)
    f1.close()

f2.close()

Answer 1

itertools.islice is designed for this :

import itertools

with open('VY_NM_VR_lin_o1_bonded_results_{k}.txt'.format(k=k)) as f1:
    # islice w/4 & None skips first four lines of f1, then generates the rest,
    # and writelines can take that iterator directly to write them all out
    f2.writelines(itertools.islice(f1, 4, None))

If you need to process the lines as you go, then skip writelines and go back to:

    for line in itertools.islice(f1, 4, None):
        ... do stuff with line ...
        f2.write(line)

Either way, you never even see the first four lines (Python is reading them and discarding them for you seamlessly).