Question of Python second loop break and indexes

Wed May 9 04:36:30 EDT 2012

//final_1 is a list of Identifier which I need to find corresponding
files(four lines) in x(x is the file) and write following four lines
in a new file.
//because the order of the identifier is the same, so after I find the
same identifier in x , the next time I want to start from next index
in x,which will save time. That is to say , when the if command
satisfied ,it can automatically jump out out the second while loop and
come to the next identifier of final_1 ,meanwhile the j should start
not from the beginning but the position previous.
//when I run the code it takes too much time more than one hour and
give the wrong result....so could you help me make some improvement of
the code?
i=0
offset_1=0
while i <len(final_1):
	j = offset_1
	while j <len(x1):
		if final_1[i] == x1[j]:
			new_file.write(x1[j])
			new_file.write(x1[j+1])
			new_file.write(x1[j+2])
			new_file.write(x1[j+3])
			offset_1 = j+4
			quit_loop="True"
		if quit_loop == "True":break
		else: j=j +1
	i=i+1