Any push back like function in python?

Question

Sorry guys!!! pardon me. I'm a beginner in Python. I am writing the following code:

for line in file:
 if StartingMarker in line:
  # Here: I want to push back 'line' back in 'file'
    for nextline in file:
     if EndingMarker in line:
        # Do some Operation
print "Done"

How can I push 'line' back in 'file'?

Thanks in Advance.

Answer 1

Don't push back, yield.

def starttoend(it):
  for line in it:
    if 'START' in line:
      yield line
      break
  for line in it:
    yield line
    if 'END' in line:
      break

l = ['asd', 'zxc', 'START123', '456789', 'qwertyEND', 'fgh', 'cvb']

i = iter(l)
for line in starttoend(i):
  print line

Just use the iterator again if you need more sequences.