Tutorial slides (PDF) - Clemson University

Let's write ten integers to disk without buffering, then read them
back:
>>> f=open('frogs.dat','w+',0) # open for unbuffered reading and writing
>>> f.writelines([str(my_int) for my_int in range(10)])
>>> f.tell() # we're about to see we've made a mistake
10L # hmm... we seem short on stuff
>>> f.seek(0) # go back to the start of the file
>>> f.tell() # make sure we're there
0L
>>> f.readlines() # Let's see what's written on each line
['0123456789']# we've written 10 chars, no line returns... oops
>>> f.seek(0) # jumping back to start, let's add line returns
>>> f.writelines([str(my_int)+'\n' for my_int in range(10)])
>>> f.tell() # jumping back to start, let's add line returns
20L
>>> f.seek(0)# return to start of the file
>>> f.readline()# grab one line
'0\n'
>>>f.next() # grab what ever comes next
'1\n'
>>> f.readlines() # read all remaining lines in the file
['2\n', '3\n', '4\n', '5\n', '6\n', '7\n', '8\n', '9\n']
>>> f.close() # always clean up after yourself - no need other than courtesy!