list ,dict,tuple, or docentment all can use for in loop>
number=0
for i in file:
number+=1
if i ==3:
i=" ".join((i.strip,'word')
print(i)
read article,cursor persent position. can using "seek( number)" work it
for in stance:
f.seek(30)
flush
from cache(computer temporary storage region, for a short time store area .main function is improve pc productivity)
to disk (permanent storage area.)
