Python: rewinding one line in file when iterating with f.next()

Question

Python\'s f.tell doesn\'t work as I expected when you iterate over a file with f.next():

>>> f=open(\".bash_profile\", \"r\")
>>> f.tell()
         


        

Answer 1

Python's file iterator does a lot of buffering, thereby advancing the position in the file far ahead of your iteration. If you want to use file.tell() you must do it "the old way":

with open(filename) as fileob:
  line = fileob.readline()
  while line:
    print fileob.tell()
    line = fileob.readline()